Led lamp

ABSTRACT

An LED lamp includes: a lamp shell; a passive heat dissipating element having a heat sink, and the heat sink including fins and a base and connecting to the lamp shell; a power source disposed in the lamp shell; and a light board connecting to the heat sink and including LED chips electrically connected to the power source. A chamber of the lamp shell is formed with a first heat dissipating channel. The first heat dissipating channel has a first air inlet at an end of the lamp shell. Another end of the lamp shell has a heat dissipating hole. A second heat dissipating channel is formed in the fins and base. The second heat dissipating channel has a second air inlet. Air flows into the second air inlet, passes through the second heat dissipating channel and flow out from spaces between every adjacent two of the fins.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to the following Chinese PatentApplications No. CN 201810130085.3 filed on Feb. 8, 2018, CN201810479044.5 filed on May 18, 2018, CN 201810523952.X filed on May 28,2018, CN 201810573322.3 filed on Jun. 6, 2018, CN 201810634571.9 filedon Jun. 20, 2018, CN 201810763800.7 field on Jul. 12, 2018, CN201810763089.5 filed on Jul. 12, 2018, CN 201810972904.9 filed on Aug.24, 2018, CN 201811172470.0 filed on Oct. 9, 2018, CN 201811295618.Xfiled on Nov. 1, 2018, CN 201811299410.5 filed on Nov. 2, 2018, CN201811347198.5 filed on Nov. 13, 2018, CN 201811378174.6 filed on Nov.19, 2018, and CN 201811466198.7 filed on Dec. 3, 2018, the disclosuresof which are incorporated herein in their entirety by reference.

FIELD OF THE INVENTION

The invention relates to lighting, particularly to high-power LED lamps.

BACKGROUND OF THE INVENTION

Because LED lamps possess advantages of energy saving, high efficiency,environmental protection and long life, they have been widely adopted inthe lighting field. For LED lamps used as an energy-saving green lightsource, a problem of heat dissipation of high-power LED lamps becomesmore and more important. Overheating will result in attenuation oflighting efficiency. If waste heat from working high-power LED lampscannot be effectively dissipated, then the life of LED lamps will bedirectly negatively affected. As a result, in recent years, solution ofthe problem of heat dissipation of high-power LED lamps is an importantissue for the industry.

In some applications, there may be a weight limit for a whole LED lamp.For example, when an LED lamp is provided with a lamp head with aspecific specification and the LED lamp is used in a hanging manner, amaximum weight of the LED lamp is subject to a limited range.Accordingly, other than necessary components such as a power source, alamp cover and a lamp shell, weight of a heat sink of an LED lamp isrestricted to a limited range. For those high-power LED lamps (alsoknown as LED high-bay lights), such as those using power of 150 W˜300 W,their luminous flux can reach about 20000 lumens˜45000 lumens. In thiscase, a heat sink must dissipate heat from an LED lamp with 20000˜45000lumens under its weight limit.

Currently mainly available heat dissipating components for LED lamps arefans, heat pipes, heat sinks or their combination to dissipate heat ofan LED lamp by thermal conduction, convection and/or radiation. Under acondition of merely adopting passive heat dissipation (without a fan),an overall effect of heat dissipation depends upon thermal conductivityand heat dissipation area of material of the heat sink. Under acondition of the same thermal conductivity, heat sinks merely rely onboth convection and radiation to dissipate heat regardless of typesthereof. Heat dissipating ability of these two types of heat sinks is inproportion to heat dissipating area thereof. Thus, under a preconditionof a weight limit for a heat sink, how to improve efficiency of heatdissipation of a heat sink is an important way to enhance quality of LEDlamps and reduce cost of LED lamps.

A currently available LED lamp generally includes a light source, a heatsink, a power source, a lamp shell and a lamp cover. The light source isfastened onto the heat sink. The power source is disposed in the lampshell. The lamp shell connects to the heat sink. The lamp shell includesa head for connecting a lamp socket. Currently available LED lamps havethe following drawbacks:

1. Concerns with designs of heat sinks:

Under a condition of merely adopting a manner of passive heatdissipation within the weight limit of a heat sink, a problem of heatdissipation of LEDs of some high-power LED lamps may exist so that heatfrom working LEDs cannot be dissipated timely. Life of these LEDs willbe affected after long term use. As an example, a heat sink may includefins, but a relative positional relationship between the fins and LEDsmay be arranged so as to make a heat conduction path of the heat fromthe LEDs to the fins too long to dissipate heat of LEDs fast enough.

Further, certain convection designs between fins of a heat sink may beimpractical or ineffective. For example, Chinese patent No. 2047174890teaches a fanless LED projection light. There is no convection frombottom to top between wing sheets of '489's heat sink so that heat inthe air cannot be timely dissipated after heat in the wing sheets hasbeen radiated to the air. As a result, the temperature of air around thewing sheets increases. An important factor of affecting thermalradiation of the wing sheets is a temperature difference between thewing sheets and air therearound. Accordingly, a raise in air temperaturewould affect thermal radiation of the wing sheets.

Moreover, certain structural designs of fins of a heat sink may beimpractical or ineffective. For example, Chinese patent No. 107345628Ateaches an LED lamp whose fins in a direction of a height of the LEDlamp have the same width. For heat dissipation of an LED lamp, fins nearLEDs in a direction of a height of the LED lamp are mainly used forconducting heat of the LEDs to the fins and the fins away from the LEDsare used for dissipating heat to air therearound by thermal convectionand radiation. The fins away from the LEDs dissipate heat to airtherearound by thermal convection and radiation, so no excessive heatdissipating area is required. However, the design of fins of the LEDlamp disclosed by '628 would cause increase of overall weight of the LEDlamp without proportioned increase of efficiency of heat dissipation.

In addition to the above issues, fins of a heat sink may still have somestructural problems. For example, a high-power LED lamp with a largersize, whose width may be above 150 mm and height may be above 180 mm,should match fins with correspondingly larger length and width. If suchfins lack sufficient support, they tend to be skewed in assembling. Inaddition, an unreasonable design of radial outlines of fins would reducean effect of heat dissipation and may not properly match a lamp.

2. Concerns with arrangement of power sources:

For some high-power LED lamps, such as power of up to 150 W˜300 W, heatdissipation of their power sources is also important. If heat from apower source of a working LED lamp cannot be dissipated timely, thenlife of some electronic components will be affected and finally life ofa whole lamp will be affected. Usually, there is no effective heatmanagement between a heat sink and a power source in a currentlyexisting LED lamp. This will result in mutual influence between heat ofa heat sink and a power source. For example, Chinese patent No.2031903640 teaches a heat dissipating structure with double-channeledair convection for a lamp. No effective thermal isolation is providedbetween its fins and a chamber (a part of the chamber is directly formedon the heat sink) receiving a power source or between its light sourceand the chamber receiving the power source. Heat from the fins and thelight source may therefore directly enter the chamber through thermalconduction to affect the power source in the chamber.

Furthermore, certain layouts of electronic components of a power sourcemay cause problems for heat dissipation. For example, laying outheat-generating components (such as resistors, inductors andtransformers) together may be disadvantageous to forming of temperaturegradients between the heat-generating components and air therearound soas to adversely affect efficiency of heat radiating from theheat-generating components to air. It is noted that when external air isthermally transferred to the power source and no particular design isprovided, then bugs and dust tends to be attached on the power source toaffect heat dissipation of the power source.

Besides the problem of heat dissipation, high-power LED lightingpossesses relatively heavier weight and a higher working temperature, soa requirement of structure of high mechanic strength under a hightemperature should be considered. A general high-power LED lighting isassembled by screwing components to connect. Considering a requirementof distance of insulated creepage, a lamp neck above a heat sink usuallyadopts a plastic material. The most common structure is that a casing ofa plastic element is together with a lamp head thread, the lamp head isscrewed to the casing and riveting pinholes are added to implementpositioning connection. Connection using screws not only requirescomplicated process in manufacture, but also cost is higher. Thus,mechanic connection of high-power LED lighting is another importantissue for these products.

When packing and shipping of LED lamps are involved, a lamp cover of anLED lamp protrudes from a light board. For example, in Chinese patentNo. 107345628A, the lamp cover of the LED lamp may touch externalobjects to cause damage. Therefore, when packing and shipping, the lampcover needs to be particularly protected to avoid damage resulting fromcollision. This will increase packing cost.

When considering light emission of LED lamps, usually, under an idealcondition, light from an LED lamp is expected to be projected onto aspecific area under the LED lamp to guarantee intensity in this area.However, in fact, a considerably large part of light may be projected toa lateral area to cause waste of light and decrease of output efficiencyof light. For example, Chinese patent No. 107345628A discloses a solidstate lamp including a solid state light source on a circuit board. Apart of the solid state light source is laterally disposed. A lamp isusually used with the light source. A solid state light source which islaterally disposed may use a lamp to reflect its light to projectdownward. In the process of reflection, there is typically light loss.Thus, efficiency of light emission will be adversely affected.

Furthermore, for circuits, a bias of conventional driving circuits isgenerated by acquiring voltage division on a mother line. Inapplications of HID-LED (High intensity Discharge-LED), however, largecapacitors are usually used in conventional biasing circuits to avoidexcessive power waste. This may cause a situation where the HID-LEDcannot be lit up immediately. Typical starting time of general biasingis about 1 second. This can affect convenience of use.

OBJECT AND SUMMARY OF THE INVENTION

The LED lamp described in the present disclosure includes an LED (lightemitting diode) lamp including a lamp shell, a passive heat dissipatingelement comprising a heat sink, the heat sink comprising fins and abase, and the heat sink connecting to the lamp shell; a power sourcedisposed in the lamp shell; and a light board, connecting to the heatsink, and comprising LED chips electrically connected to the powersource. A chamber of the lamp shell is formed with a first heatdissipating channel. The first heat dissipating channel has a first airinlet at an end of the lamp shell, another end of the lamp shell has aheat dissipating hole, a second heat dissipating channel is formed inthe fins and base, the second heat dissipating channel has a second airinlet, and air flows into the second air inlet and passes through thesecond heat dissipating channel and finally flows out from spacesbetween every adjacent two of the fins.

The light board may be formed with an aperture communicatingsimultaneously with both the first heat dissipating channel and thesecond heat dissipating channel.

The aperture may be located in a central region of the light board, andthe aperture may form an air intake of both the first heat dissipatingchannel and the second heat dissipating channel.

A weight of the heat sink may account for at least 50% of that of theLED lamp, and a volume of the heat sink may account for at least 20% ofan overall volume of the LED lamp.

A volume of the heat sink may account for 20%˜60% of an overall volumeof the LED lamp.

In certain embodiments, the heat sink comprises first fins and secondfins, bottoms of both the first fins and the second fins in an axis ofthe LED lamp connected to the base, the first fins interlace with thesecond fins at regular intervals, and each of the second fins is of aY-shape.

The LED lamp may further comprise a lamp cover with a light outputsurface and an end surface, wherein the end surface is formed with avent, air flows into both the first heat dissipating channel and thesecond heat dissipating channel through the vent, the first air inlet isprojected onto the end surface in an axis of the LED lamp to occupy anarea on the end surface, which is defined as a first portion, anotherarea on the end surface is defined as a second portion, and the vent inthe first portion is greater than the vent in the second portion inarea.

Various aspects of the disclosed embodiments may result in certainadvantages, as described below.

1. Heat in the first heat dissipating channel from the working powersource can be brought out. The second heat dissipating channel canenhance convection of the heat sink. Both the first and second heatdissipating channels can enhance efficiency of natural convection of thewhole lamp so as to reduce required area of heat dissipation of the heatsink.

2. The aperture may simultaneously communicate with both the first heatdissipating channel and the second heat dissipating channel and theapertures may be located in a central region of the light board so thatthe aperture forms a common air intake of both the first heatdissipating channel and the second heat dissipating channel. As aresult, area of the light board may be occupied as little as possible toprevent the region of the light board where LED chips are placed frombeing occupied by other air intakes.

3. Weight of the heat sink may account for above 50% of overall weightof the LED lamp, and volume of the heat sink may account for above 20%of overall volume of the LED lamp. Under a condition of the same thermalconductivity of the heat sink, the larger the heat sink accounting for apercentage of overall volume of the LED lamp is, the larger theavailable area of heat dissipation is. As a result, to a certain extent,when volume of the heat sink accounts for above 20% of overall volume ofthe LED lamp, there is more usable space in the heat sink to increasearea of heat dissipation.

4. By using Y-shaped second fins, the heat sink can obtain more area ofheat dissipation under the same volume.

5. The vent in the first portion may have greater area than the vent inthe second portion, which may be advantageous to most air entering thefirst heat dissipating channel so as to improve heat dissipation to thepower source and to prevent electronic components of the power sourcefrom aging rapidly due to being heated.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed descriptions, given by way of example, and notintended to limit the present invention solely thereto, will be best beunderstood in conjunction with the accompanying figures:

FIG. 1 is a structural schematic view of one embodiment of an LED lampaccording to aspects of the invention;

FIG. 2 is a schematic cross-sectional view of the LED lamp of FIG. 1;

FIG. 3 is an exploded view of the LED lamp of FIG. 1;

FIG. 4 is a schematic cross-sectional view of the LED lamp of FIG. 1,which shows the first heat dissipating channel and the second heatdissipating channel;

FIG. 5 is a perspective view of the LED lamp of FIG. 1;

FIG. 6 is a structural schematic view of FIG. 5 without the light outputsurface;

FIG. 7 is a schematic view of light projection of the LED lamp of FIG.1;

FIG. 8 is a light pattern of FIG. 7;

FIG. 9 is an exploded view of another embodiment of an LED lampaccording to aspects of the invention, which shows a shading ring;

FIG. 10 is a perspective view of another embodiment of an LED lampaccording to aspects of the invention;

FIG. 11 is a schematic view of FIG. 10 without the light output surface;

FIG. 12 is a cross-sectional view of another embodiment of the LED lampaccording to aspects of the invention, which shows the flat light outputsurface;

FIG. 13a is a schematic view of an embodiment of the combination of thelight board and the lamp cover;

FIG. 13b is a schematic view of another embodiment of the combination ofthe light board and the lamp cover;

FIG. 13c is a schematic view of still another embodiment of thecombination of the light board and the lamp cover;

FIG. 14 is a schematic view of yet another embodiment of the combinationof the light board and the lamp cover;

FIG. 15 is a schematic view of an end surface of the lamp cover of anembodiment;

FIG. 16 is a schematic view of an end surface of the lamp cover,according to another embodiment of the present invention;

FIG. 17 is another view of the end surface of FIG. 16;

FIGS. 18a ˜18 i are schematic views of some embodiments of the lampcover;

FIG. 19a is a cross-sectional view of the heat sink, according toanother embodiment of the present invention;

FIG. 19b is a schematic view of an LED lamp using the heat sink of FIG.19 a;

FIG. 20 is a cross-sectional view of an LED lamp without a lamp cover,according to another embodiment of the present invention;

FIG. 21 is a perspective view of an LED lamp, according to anotherembodiment of the present invention;

FIG. 22 is a cross-sectional view of the LED lamp of FIG. 21;

FIG. 23 is a top view of the heat sink of the LED lamp of FIG. 21;

FIG. 24 is an enlarged view of portion E in FIG. 23;

FIG. 25 is a schematic view showing a vortex formed by air near thesecond fins according to another embodiment of the present invention;

FIG. 26 is a partially schematic view of the heat sink of anotherembodiment;

FIG. 27 is a main view of an LED lamp of another embodiment;

FIG. 28 is a main view of an LED lamp of another embodiment;

FIG. 29 is a bottom view of the LED lamp of FIG. 1 without the lampcover;

FIG. 30 is an enlarged view of portion A in FIG. 29;

FIG. 31 is a cross-sectional view of an LED lamp, according to anotherembodiment of the present invention;

FIG. 32 is an enlarged view of the LED lamp of portion C in FIG. 31;

FIG. 33 is a perspective view of a lamp cover, according to anotherembodiment of the present invention;

FIG. 34 is a schematic view of an embodiment of the combination of thelight board and the lamp cover;

FIG. 35 is a top view of FIG. 34;

FIGS. 36a ˜36 m are schematic views of some embodiments of the heatsink;

FIGS. 37a ˜37 d are schematic views of some embodiments of the heatsink;

FIGS. 38a ˜38 i are top views of some embodiments of the heat sink;

FIG. 39 is a top view of an embodiment of the heat sink;

FIG. 40 is a schematic view of the combination of the fins and the LEDchips of an embodiment;

FIG. 41 is a schematic view of the combination of the fins and the LEDchips, according to some embodiments of the present invention;

FIG. 42 is a schematic view of an embodiment of the light board;

FIG. 43 is a schematic view of another embodiment of the light board;

FIGS. 44a ˜44 f are schematic views of some embodiments of the lightboard;

FIGS. 45a ˜45 g are top views of some embodiments of the light board;

FIGS. 46a ˜46 c are perspective views of the power source, according tosome embodiments of the present invention;

FIG. 46d is a main view of the power source of the embodiment of FIGS.46a ˜46 c;

FIG. 47 is a schematic view of the power source, according to oneembodiment of the present invention;

FIG. 48 is a main view of the counterweight of FIG. 47;

FIG. 49 is a side view of the counterweight of FIG. 48;

FIG. 50 is a schematic view of a transformer, according to oneembodiment of the present invention;

FIG. 51 is a schematic of the power source, according to an embodimentof the present invention;

FIG. 52 is a schematic of the power source of another embodiment;

FIGS. 53a ˜53 c are schematic views of some embodiments of the powersource board;

FIG. 54 is a cross-sectional view of the LED lamp of an embodiment;

FIG. 55 is a cross-sectional view of the LED lamp of an embodiment;

FIG. 56 is a schematic view of the combination of the power source andthe sleeve, according to some embodiments of the present invention;

FIG. 57 is an enlarged view of portion B in FIG. 2;

FIG. 58 is a partially schematic view of an LED lamp;

FIGS. 59a ˜59 b are perspective views of the lamp neck of an embodiment;

FIG. 59c is a perspective view of the lamp neck of another embodiment;

FIG. 60 is a perspective view of the sleeve of an embodiment;

FIG. 61 is a cross-sectional view of the LED lamp of another embodiment;

FIG. 62 is a schematic view of an arrangement of the convection channelsof the LED lamp of FIG. 61;

FIG. 63 is a main view of an embodiment of the LED lamp without the heatsink;

FIG. 64 is an exploded view of the LED lamp of FIG. 63;

FIG. 65a is an exploded view of the lamp shell of the LED lamp ofanother embodiment;

FIG. 65b is a schematic assembling view of FIG. 65 a;

FIG. 65c ˜65 d are exploded views of the LED lamp with the lamp shell ofFIG. 65 a;

FIG. 65e is a cross-sectional view of the LED lamp with the lamp shellof FIG. 65 a;

FIG. 66 is a main view of the LED lamp, according to one embodiment ofthe present invention;

FIG. 67 is a schematic view of the combination of the LED lamp with alampshade, according to one embodiment of the present invention;

FIG. 68 is a schematic view of another embodiment of the LED lamp;

FIG. 69 is a main view of the LED lamp, according to one embodiment ofthe present invention;

FIGS. 70a ˜70 c are a schematic view of the combination of the LED lampwith a lampshade, according to some embodiments of the presentinvention;

FIG. 71 is a layout diagram of the LED module, according to anembodiment of the present invention;

FIG. 72 is an enlarged view of portion D in FIG. 71;

FIG. 73 is an enlarged view of the LED module of another embodiment;

FIG. 74 is a block diagram of the power module of an embodiment of theinvention;

FIG. 75 is a circuit diagram of an EMI reduction circuit of anembodiment of the invention;

FIG. 76 is a circuit diagram of a rectifier and a filter of anembodiment of the invention;

FIG. 77 is a circuit diagram of a PFC of an embodiment of the invention;

FIG. 78 is a circuit diagram of a power converter of an embodiment ofthe invention;

FIG. 79 is a circuit diagram of a bias generator of an embodiment of theinvention;

FIG. 80 is a circuit diagram of a bias generator of another embodimentof the invention;

FIG. 81 is a circuit diagram of a temperature detector of an embodimentof the invention; and

FIG. 82 is a circuit diagram of a temperature compensator of anembodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

To make the present invention understandable and readable, the followingdisclosure will now be described in the following embodiments withreference to the drawings. The following descriptions of variousembodiments of this invention are presented herein for purpose ofillustration and giving examples only. It is not intended to beexhaustive or to be limited to the precise form disclosed. These exampleembodiments are just examples and many implementations and variationsare possible without the details provided herein. Some terms mentionedin the following description, such as “in an axis”, “above” or “under”,are used for clear structural relationship of elements, but not a limitto the present invention. In the present invention, the terms“perpendicular”, “horizontal” and “parallel” are defined in a range of±10% based on a standard definition. For example, “perpendicular”(perpendicularity) means the relationship between two lines which meetat a right angle (90 degrees). However, in the present invention,“perpendicular” may encompass a range from 80 degrees to 100 degrees. Inaddition, “using condition” or “using status” mentioned in the presentdisclosure means a “head-up” hanging scenario. Exceptions will beparticularly described.

FIG. 1 is a structural schematic view of an embodiment of an LED lampaccording to certain aspects of the invention. FIG. 2 is a schematiccross-sectional view of the LED lamp of FIG. 1. FIG. 3 is an explodedview of the LED lamp of FIG. 1. As shown in the figures, the LED lampincludes a heat sink 1, a lamp shell 2, a light board 3, a lamp cover 4and a power source 5. In this embodiment, the light board 3 is connectedto the heat sink 1 by attachment for rapidly transferring heat from thelight board 3 to the heat sink 1 when the LED lamp is working. In someembodiments, the light board 3 is riveted to the heat sink 1. In someembodiments, the light board 3 is screwed to the heat sink 1. In someembodiments, the light board 3 is welded to the heat sink 1. In someembodiments, the light board 3 is adhered to the heat sink 1. In thisembodiment, the lamp shell 2 is connected to the heat sink 1, the lampcover 4 covers the light board 3 to make light emitted from the lightboard 3 pass through the lamp cover to project out. The power source 5is located in a chamber of the lamp shell 2 and the power source 5 is ECto the LED chips 311 for providing electricity.

FIG. 4 is a schematic cross-sectional view of the LED lamp. As shown inFIGS. 2 and 4, the chamber of the lamp shell 2 of this embodiment isformed with a first heat dissipating channel 7 a. An end of the firstheat dissipating channel is formed with a first air inlet 2201. Anopposite end of the lamp shell 2 is formed with a venting hole 222 (atan upper portion of the lamp neck 22). Air flows into the first heatdissipating channel 2201 and flows out from the venting hole 222 forbringing out heat in the first heat dissipating channel 7 a (primarily,heat of the working power source 5). As for the path of heatdissipation, heat generated from the heat-generating components of theworking power source 5 is transferred to air (around the heat-generatingcomponents) in the first heat dissipating channel 7 a by thermalradiation first, and then external air enters the first heat dissipatingchannel 7 a by convection to bring out internal air to make heatdissipation. In this embodiment, the venting hole 222 at the lamp neck22 can also make direct heat dissipation.

As shown in FIGS. 1, 2 and 4, a second heat dissipating channel 7 b isformed in the fins and the base 13 of the heat sink 1. The second heatdissipating channel 7 b has a second air inlet 1301. In this embodiment,the first air inlet 2201 and the second air inlet 1301 share the sameopening formed on the light board 3. This will be described in moredetail later. Air flows from outside of the LED lamp into the second airinlet 1301, passes through the second heat dissipating channel 7 b andfinally flows out from spaces between the fins 11 so as to bring outheat of the fins 11 to enhance heat dissipation of the fins 11. As forthe path of heat dissipation, heat generated from the LED chips isconducted to the heat sink 1, the fins 11 of the heat sink 1 radiate theheat to surrounding air, and convection is performed in the second heatdissipating channel 7 b to bring out heated air in the heat sink 1 tomake heat dissipation.

As shown in FIGS. 1 and 4, the heat sink 1 is provided with a third heatdissipating channel 7 c formed between adjacent two of the fins 11 or ina space between two sheets extending from a single fin 11. A radialouter portion between two fins 11 forms an intake of the third heatdissipating channel 7 c. Air flows into the third heat dissipatingchannel 7 c through the radial outer portion of the LED lamp to bringout heat radiated from the heat sink 11 to air.

FIG. 5 is a perspective view of the LED lamp of an embodiment, whichshows assembling of the heat sink 1 and the lamp cover 4. FIG. 6 is astructural schematic view of FIG. 5 without the light output surface 43.As shown in FIGS. 5 and 6, in this embodiment, the lamp cover 4 includesa light output surface 43 and an end surface 44 with a vent 41. Airflows into both the first heat dissipating channel 7 a and the secondheat dissipating channel 7 b through the vent 41. When the LED chips 311(shown in FIG. 6) are illuminated, the light passes through the lightoutput surface 43 to be projected from the lamp cover 4. In thisembodiment, the light output surface 43 may use currently availablelight-permeable material such as glass, PC, etc. The term “LED chip”mentioned in all embodiments of the invention means all light sourceswith one or more LEDs (light emitting diodes) as a main part, andincludes but is not limited to an LED bead, an LED strip or an LEDfilament. Thus, the LED chip mentioned herein may be equivalent to anLED bead, an LED strip or an LED filament. As shown in FIG. 5, in thisembodiment, the ratio of area of the light output surface 43 to area ofthe end surface 44 is 4˜7. Preferably, the ratio of area of the lightoutput surface 43 (area of a single side of the light output surface 43,i.e. area of surface of the side away from the LED chips 311) to area ofthe end surface 44 (area of a single side of the end surface 44, i.e.area of surface of the side away from the LED chips 311, including areaof the vent 41) is 5˜6. More preferably, the ratio of area of the lightoutput surface 43 to area of the end surface 44 is 5.5. The end surface44 is used for allowing air to pass to enter both the first heatdissipating channel 7 a and the second heat dissipating channel 7 b. Thelight output surface 43 allows light from the light source to output. Asa result, a balance can be accomplished between the light output and theheat dissipation. In this embodiment, to satisfy the requirement of airintake of both the first heat dissipating channel 7 a and the secondheat dissipating channel 7 b, the ratio of area of the lamp cover 4 toarea of the end surface 44 is 6˜7. As a result, a balance can beaccomplished between the light output and air required by the heatdissipation.

In this embodiment, area of the light output surface 43 (area of asingle side of the light output surface 43, i.e. area of surface of theside away from the LED chips 311) is above three times as large as areaof light emitting surface of all the LED chips 31 but does not exceedten times. Width of the light output region can be controlled when it isprovided sufficiently.

As shown in FIGS. 5 and 6, in this embodiment, an inner reflectingsurface 4301 is disposed inside the light output surface 43 of the lampcover 4. The inner reflecting surface 4301 is disposed in the innercircle of the array of LED chips 311. In an embodiment, an outerreflecting surface 4302 is disposed in the outer circle of the array ofLED chips 311. The outer reflecting surface 4302 corresponds to the LEDchips 311 on the light board 3. The arrangement of both the innerreflecting surface 4301 and the outer reflecting surface 4302 is usedfor adjusting a light emitting range of the LED chip set 31 to make thelight concentrated and to increase brightness in a local area. Forexample, under the condition of the same luminous flux, illuminance ofthe LED lamp can be increased. In one example, all the LED chips 311 inthis embodiment are mounted on the bottom side of the light board 3 (ina using status). In this embodiment, the LED lamp of the presentembodiment do not emit lateral light from the LED chips 311. Whenworking, the primary light emitting surfaces of the LED chips 311 arecompletely downward. At least 60% of the light from the LED chips 311are emitted through the light output surface 43 without reflection. As aresult, in comparison with those LED lamps with lateral light (thelateral light is reflected by a cover or a lampshade to be emitteddownward, and in theory there must be part of light loss in the processof reflection.) The LED chips 311 in this embodiment possess betterlight emitting efficiency. In one example, under the condition of thesame lumen value (luminous flux), the LED lamp in the present embodimentpossesses higher illuminance. And the emitted light can be concentratedto increase illuminance in a local area by the arrangement of both theinner reflecting surface 4301 and the outer reflecting surface 4302, forexample, in an area under the LED lamp between 120 degrees and 130degrees (a light emitting range under the LED lamp between 120 degreesand 130 degrees). When the LED lamp is installed at a relatively highposition, in the same angular range of light emitting, the lit area ofthe LED lamp still satisfies the requirement and illuminance in thisarea can be higher. FIG. 7 is a schematic view of light transmission ofthis embodiment and FIG. 8 is a light pattern of FIG. 7. As shown inFIGS. 5-8, in the aspect of the light emitting effect, in the projectedarea of the LED lamp, i.e. the projected area M under the LED lamp,there is a light concentrating area m within the projected area M, theLED lamp including the reflecting surface reflects at least part oflight from the LED chips 311 onto the light concentrated area m toincrease brightness of the light concentrated area m. The reflectingsurface includes the inner reflecting surface 4301 and the outerreflecting surface 4302. Both the inner reflecting surface 4301 and theouter reflecting surface 4302 reflect at least part of light from theLED chips 311 onto the light concentrated area m. Preferably, in thisembodiment, at least 5% of luminous flux of the light source isreflected to pass through the light output surface 43. In practice,total luminous flux of the light reflected by both the inner reflectingsurface 4301 and the outer reflecting surface 4302 and emitted throughthe light output surface 43 is at least 1000 lm. Preferably, totalluminous flux of the light reflected by both the inner reflectingsurface 4301 and the outer reflecting surface 4302 and emitted throughthe light output surface 43 is at least 1500 lm. Total luminous flux ofthe light reflected by the outer reflecting surface 4302 is greater thanthat of the light reflected by the inner reflecting surface 4301. Thisshows that, about the problem of glare resulting from an LED lamp withhigh lumen, disposing the outer reflecting area 4302 can reflectconsiderable part of lateral luminous flux. This can significantlyreduce the glare. In this embodiment, the light concentrated area m isan annular region. In this embodiment, a center angle between an inneredge of the light concentrated area m and an axis of the LED lamp is 20degrees, and a center angle between an outer edge of the lightconcentrated area m and an axis of the LED lamp is 50 degrees. In thisembodiment, luminous flux of the light projected by the LED lamp ontothe light concentrated area m accounts for 35%˜50% of the total luminousflux, so that the light concentrated area m possesses a better lightingeffect. In addition, by the arrangement of both the inner reflectingsurface 4301 and the outer reflecting surface 4302, not only can thelateral light be reduced to prevent glare, but also at least part oflight from the LED chips 311 can be reflected onto the projected area Mto enhance illuminance in the projected area M.

The inner reflecting surface 4301 is used for reflecting part of lightemitted from the innermost LED chips 311 of the LED chip set 31. Theouter reflecting surface 4302 is used for reflecting part of lightemitted from the outermost LED chips of the LED chipset 31. Theoutermost LED chips 311 are greater than the innermost LED chips 311 innumber. The outer reflecting surface 4302 is greater than the innerreflecting surface 4301 in area. Because the outermost portion of theLED chip set 31 includes more LED chips than the innermost portion,larger reflecting area is beneficial to regulate light output.

In this embodiment, the inner reflecting surface 4301 and the outerreflecting surface 4302 have first area A1 and second area A2,respectively. The LED chips 311 in the outermost portion of the LED chipset 31 and in the innermost portion of the LED chip set 31 are N1 and N2in number, respectively. Their relationship is:

(A1/N1):(A2/N2)=0.4˜1

When the ratio of area of the inner reflecting surface 4301corresponding to a single LED chip 311 in the innermost portion of theLED chip set 31 to area of the outer reflecting surface 4302corresponding to a single LED chip 311 in the outermost portion of theLED chip set 31 falls in the above range, both the LED chips 311 in theinnermost portion of the LED chip set 31 and the LED chips 311 in theoutermost portion of the LED chip set 31 have a better effect of lightoutput.

As shown in FIG. 6, an inner edge of the inner reflecting surface 4301abuts against the light board 3 to prevent light from passing throughgaps between the inner reflecting surface 4301 and the light board 3 toavoid loss of part of light. Identically, an inner edge of the outerreflecting surface 4302 abuts against the light board 3 to prevent lightfrom passing through gaps between the outer reflecting surface 4302 andthe light board 3 to avoid loss of part of light.

As shown in FIG. 2, in this embodiment, an angle a is formed between twoextending lines of both the inner and outer reflecting surfaces 4301,4302. The angle a is between 80 degrees and 150 degrees. Preferably, theangle a is between 90 degrees and 135 degrees. More preferably, theangle a is between 100 degrees and 120 degrees. A reflecting-cup-likestructure is formed between the inner and outer reflecting surfaces4301, 4302 so as to control a light output range of the LED chips 311 orincrease local intensity. In this embodiment, an angle between the outerreflecting surface 4302 and the light board 2 is 30 to 60 degrees. Insome embodiments, the angle is 40 to 50 degrees.

As shown in FIG. 2, in this embodiment, the inner reflecting surface4301 is lower than the outer reflecting surface 4302 in height. Theheight means a height of each of the both in an axis of the LED lamp. Bythe configuration of the inner reflecting surface 4301 being lower thanthe outer reflecting surface 4302 in height, decrease of a lightdistribution under the LED lamp can be avoided and a central portion ofthe light distribution region of the LED lamp can be prevented to be adark part. In this embodiment, height of the outer reflecting surface4302 in the axis of the LED lamp is not greater than 20 mm. Preferably,height of the outer reflecting surface 4302 in the axis of the LED lampis not greater than 15 mm. On the other hand, to control overall heightof the LED lamp, height of the outer reflecting surface 4302 accountsfor not over 9% of overall height of the LED lamp. Preferably, height ofthe outer reflecting surface 4302 accounts for not over 6% of overallheight of the LED lamp. As for functions of the outer reflecting surface4302, in some embodiments, height of the outer reflecting surface 4302has to account for above 2% of overall height of the LED lamp.Preferably, in some embodiments height of the outer reflecting surface4302 accounts for above 3% of overall height of the LED lamp. In oneexample, comprehensively considering control of height of the LED lampand functions of reflection, light concentration, anti-glare, etc., itis necessary that height of the outer reflecting surface 4302 accountsfor 2%˜9% of overall height of the LED lamp. Preferably, height of theouter reflecting surface 4302 accounts for 3%˜6% of overall height ofthe LED lamp.

In the LED lamps in some embodiments, both the inner and outerreflecting surfaces can be omitted, for example, a shading ring 47 maybe disposed. As shown in FIG. 9, the shading ring 47 is disposed on aperiphery of the lamp cover 4 to improve efficiency of light output ofthe lamp. A surface of the shading ring 47 possesses a reflecting effect(similar to the outer reflecting surface 4302 as mentioned in theprevious embodiment). When the lamp cover 4 is attached on the heat sink1, the shading ring 47 nears a periphery of the light board 3, forexample, an outer diameter of the shading ring 47 is the same as orslightly greater than that of the light board 3.

As show in FIGS. 5 and 6, in this embodiment, in order to prevent dustfrom covering on the LED chips 311 to reduce light efficiency of the LEDchips or affect heat dissipation of the LED chips 311, the LED chips 311may be received in a sealed room. For example, a sealed chamber 9 isformed between the light output surface 43, the inner reflecting surface4301, the outer reflecting surface 4302 and the light board 3 (this term“sealed” mentioned here may mean “without obvious pores”, not includingunavoidable gaps in an assembling process). In some embodiments, whenomitting both the inner and outer reflecting surfaces 4301, 4302, thesealed chamber 9 is formed between the light output surface 43 and thelight board 3 or between the light output surface 43, the heat sink 1and the light board 3.

FIG. 10 is a perspective view of another embodiment of the LED lamp ofthe invention. It differs from the above embodiment by holes formed inthe chamber 9. FIG. 11 is a schematic view of FIG. 10 without the lightoutput surface 43. As shown in FIGS. 10 and 11, in some embodiments, achamber 9 is formed between the light cover 4 and the light board 3. Indetail, the chamber 9 is formed between the light output surface 43, theinner reflecting surface 4301, the outer reflecting surface 4302 and thelight board 3 and the LED chips of the light board 3 are located in thechamber 9. The chamber 9 has first apertures 91 and second apertures 92.The first apertures 91 are configured to communicate with the outside,and the second apertures 92 are configured to communicate simultaneouslywith both the first heat dissipating channel 7 a and the second heatdissipating channel 7 b. In an aspect of heat dissipation, airconvection is formed in the chamber 9 to bring out part of heatgenerated from the LED chips 311, and outside air flows into the LEDlamp through the chamber 9 so as to enhance convection in both the firstheat dissipating channel 7 a and the second heat dissipating channel 7b. In some embodiments, both the inner and outer reflecting surfaces4301, 4302 may be omitted. In one example, a chamber 9 is formed betweenthe light output surface 43 and the light board 3.

As shown in FIG. 10, in some embodiments, the light output surface 43 isprovided with a hole to form the first apertures 91. Preferably, thefirst apertures 91 are annularly located at a circumferential portion ofthe light output surface 43 to make it not affect the effect of lightpenetration of the light output surface 43. In an aspect of structure,the light output surface 43 may be thermally deformed while the LED lampis working. The first apertures 91 makes the light output surface 43have a deformable space to prevent the light output surface 43 frombeing deformed to press the heat sink and cause damage of the lightoutput surface 43. In this embodiment, the first apertures 91 areannularly located at a circumferential portion of the light outputsurface 43. As a result, air convection can be enhanced and structuralstrength of the light output surface 43 heated can also be reinforced.

As shown in FIG. 11, in some embodiments, the inner reflecting surface4301 is provided with notches to form the second apertures 92. In thisembodiment, the second apertures 92 are annularly located at acircumferential portion of the inner reflecting surface 4301. The ratioof the number of the second apertures 92 to that of the first apertures91 is about 1:1˜2, preferably, 1:1.5. Thus, air intake and outtake canbe balanced. In other embodiments, both the first apertures 91 and thesecond apertures 92 may also be formed at other portions of the lampcover 4 such as the light board 3 or the base 13 of the heat sink 1.

As shown in FIGS. 10 and 11, in some embodiments, a chamber 9 is formedbetween the light cover 4 and the light board 3. In detail, the chamber9 is formed between the light output surface 43, the inner reflectingsurface 4301, the outer reflecting surface 4302 and the light board 3and the LED chips 311 of the light board 3 are located in the chamber 9.The chamber 9 has pressure release apertures to prevent temperature andpressure in the chamber from being raised by the working LED chips 311.The pressure release aperture may be the first apertures 91 of the lightoutput surface 43, the second apertures 92 of the inner reflectingsurface 4301, or holes at the heat sink 1 or the light board 3, whichcommunicate with the chamber 9.

As shown in FIG. 4, the distance between the light output surface 43 andthe light board 3 is gradually outwardly larger and larger so as to makethe light output surface 43 concave. Thus, in comparison with a flatsurface, such a light output surface 43 can be structurally reinforced.In addition, the gradually smooth slant of the light output surface 43does not has an angle so as to make thickness of the light outputsurface 43 even not to affect an effect of light output. Finally, in anaspect of use, the light board 3 generates heat from the light sourcewhile the LED lamp is working. If the light output surface 43 is a flatplane parallel to the horizon (the LED lamp is hung on a ceiling), thenthe heated light output surface 43 will horizontally thermally expand.As a result, the heat sink 1 may be damaged by being pressed. In thisembodiment, when the light output surface 43 is of a concave shape, itsexpansion direction will be different from the above, for example, theexpansion direction is divided into a horizontal portion and a downwardvertical portion. This can reduce the thermal expansion in thehorizontal direction to prevent the lamp cover 4 from being damaged bybeing pressed by the heat sink 1.

As shown in FIG. 12, in some embodiments, the light output surface 43may also be a flat plane, but a thermal expansion coefficient of thematerial of the light output surface 43, a distance between the lightoutput surface 43 and the heat sink 1 and resistance to deformation ofthe light output surface 43 should be seriously considered. For example,when the light output surface 43 is a flat plane, the distance betweenthe light output surface 43 and the heat sink 1 should be large enoughto guarantee expansion of the light output surface 43 not to be pressedby the heat sink 1.

In some embodiments, the light output surface 43 is provided with anoptical coating, for example, the light output surface 43 is coated witha diffusion film 431 through which light emitted from the LED chips 311passes to penetrate the lamp cover 4. In a few words, the diffusion film431 diffuses light emitted from the LED chips 311. The diffusion film431 can be disposed in various manners, for example, the diffusion filmmay be coated or cover an inner surface of the light output surface 43(as shown in FIG. 13a ), or a diffusion coating coated on the LED chips311 (as shown in FIG. 13b ), or a cloak covering the LED chips 311 (asshown in FIG. 13c ).

FIG. 14 is a schematic view of the combination of the light board 3 andthe lamp cover 4. As shown, in some embodiments, a side of the lightoutput surface 43, which nears the LED chips 311, i.e. an inner side ofthe light output surface 43, is provided with an anti-reflection coating432 to reduce reflection of light from the LED chips 311 to the lightoutput surface 43 and increase light-permeability of the light outputsurface 43. The refractive index of the anti-reflection coating 432 inthis embodiment is between the reflectivity of air and glass. Theanti-reflection coating 432 includes metal oxide which accounts 1%˜99%of overall weight of the anti-reflection coating 432. The reflectivityof the anti-reflection coating 432 is less than 2%. Metal oxide in thisembodiment may be zirconia, tin oxide, tin oxide, aluminum oxide, etc.

The diffusion film 431 (in FIG. 13) and the anti-reflection coating 432may be used together or alternatively used. It can be selected accordingto actual requirements.

FIG. 15 is a schematic view of an end surface 44 of the lamp cover 4 ofan embodiment. As shown, the ratio of a total of cross-sectional area ofthe vent 41 to overall area of the end surface 44 (area of a single sideof the end surface 44, such as the side away from the LED chips 311) is0.01˜0.7. Preferably, the ratio of a total of cross-sectional area ofthe vent 41 to overall area of the end surface 44 is 0.3˜0.6. Morepreferably, the ratio of a total of cross-sectional area of the vent 41to overall area of the end surface 44 is 0.4˜0.55. By limiting the ratioof a total of cross-sectional of the vent 41 to overall area of the endsurface 44 to the above ranges, not only can air intake of the vent 41be guaranteed, but also adjustment of area of the vent 41 is implementedunder ensuring structural strength of the end surface 44. When the ratioof area of the vent 41 to area of the end surface 44 is 0.4˜0.55, notonly can air intake of the vent 41 be guaranteed to satisfy requirementsof heat dissipation of the LED lamp, but also the vent 41 does notaffect structural strength of the end surface 44 to prevent the endsurface 44 with the vent 41 from being fragile due to collision orpressure.

FIG. 16 is a schematic view of an end surface 44 of the lamp cover 4 ofanother embodiment. As shown in FIGS. 16 and 17, a periphery of the vent41 has an enlarged thickness to form rib portions 411. An air guideopening 412 in a direction of air intake of the vent 41 is formedbetween adjacent two of the rib portions 411. A periphery of the vent 41with an enlarged thickness can enhance structural strength of the endsurface 44 to avoid reduction of overall structural strength due to thevent 41. On the other hand, the air guide opening 412 has an effect ofair guiding to make air flowing into the air guide opening 412 have aspecific direction. In addition, when the end surface 44 is beingformed, the rib potions 411 avoids reduction of overall structuralstrength of the end surface 44. Thus, the end surface 44 is hard to bedeformed because of the vent 41 to increase the yield rate ofmanufacture. In this embodiment, the rib portions 411 are formed on theside of the end surface 44, which is adjacent to the light board.

As shown in FIG. 17, the thickness of periphery of the vent 41 isgreater than that of other portions of the end surface 44 so as toimprove strength of the parts around the vent 41 and the effect of airguiding.

As shown in FIG. 15, a diameter of a maximum inscribed circle of thevent 41 is less than 2 mm, preferably, 1.0˜1.9. mm. As a result, bothbugs and most dust can be resisted, and venting efficiency of the vent41 can be kept great enough. In one example, alternatively, the vent 41defines both a length direction and a width direction, i.e. the vent hasa length and a width, and the length is greater than the width. Thelargest width of inscribed circle of the vent 41 may be less than 2 mm.In an embodiment, the largest width is from 1 mm to 1.9 mm. In addition,the largest width of the vent 41 may be greater than 1 mm. If the widthof the vent 41 is less than 1 mm, then more pressure is required to pushair to enter the vent 41, which is advanced for venting.

FIGS. 18a ˜18 g show shapes of some embodiments of the vent 41. As shownin FIGS. 18a -18 g, the vent 41 may be circular, strip-shaped, arced,trapezoidal, diamond or their combination. As shown in FIG. 18a , whenthe vent 41 is configured to be circular, its diameter should be lessthan 2 mm to resist bugs and most dust and venting efficiency of thevent 41 can be kept great enough. As shown in FIGS. 18b and 18c , whenthe vent 41 is configured to be strip-shaped or arced, its width shouldbe less than 2 mm to accomplish the above effects. As shown in FIG. 18d, when the vent 41 is configured to be trapezoidal, its lower baseshould be less than 2 mm to accomplish the above effects. As shown inFIG. 18e , when the vent 41 is configured to be round-corneredrectangular, its width should be less than 2 mm to accomplish the aboveeffects. As shown in FIGS. 18f and 18g , when the vent 41 is configuredto be triangular or drop-shaped, a diameter of its maximum inscribedcircle should be less than 2 mm.

In some embodiments, the vent 41 on the end surface 44 is multiple innumber. For example, the vents 41 may be annularly arranged on the endsurface 44 for even air intake. The vents 41 may also be radiallyarranged on the end surface 44. The vents 41 may also be irregularlyarranged.

In some embodiments, in an axial direction of the LED lamp, the ventsmay be inclined to an axis of the LED lamp. In one example, an angle isformed between an axis of the vent 41 and the axis of the LED lamp. Asshown in FIG. 18h , axes of at least part of the vents 41 are inclinedto the axis of the LED lamp, and the inclined directions of the part ofvents 41 are toward the first air inlet 2201 of the first heatdissipating channel 7 a. Thus, after air passes the part of vents 41, itwill flow to the first air inlet 2201 of the first heat dissipatingchannel 7 a to perform convection for allowing more air to flow into thefirst heat dissipating channel 7 a to dissipate heat from the powersource 6 therein. As shown in FIG. 18i , axes of at least part of thevents 41 are inclined to the axis of the LED lamp, and the inclineddirections of the part of vents 41 are toward the second air inlet 1301of the second heat dissipating channel 7 b. Thus, after air passes thepart of vents 41, it will flow to the second air inlet 1301 of thesecond heat dissipating channel 7 b to perform convection for allowingmore air to flow into the second heat dissipating channel 7 b todissipate heat from the heat sink 1 therein.

In FIG. 18 a, there are two broken lines on the end surface 44. Theinner broken line represents a position the first air inlet 2201 (asshown in FIG. 2) is projected onto the end surface 44. The region withinthe inner broken line is defined as a first portion (first openingregion 433). The region between the inner circle and the outer circle isdefined as a second portion (second opening region 434). In thisembodiment, the first air inlet 2201 is projected onto the end surfacein an axis of the LED lamp to occupy an area on the end surface 44, itis the first portion (first opening region 433). The other area on theend surface 44 is the second portion (second opening region 434). Thevent 41 in the first portion is greater than the vent 41 in the secondportion in area. Such an arrangement is advantageous to making most airflow into the first heat dissipating channel 7 a for better effect ofheat dissipation to the power source 5 and reduction of rapidly aging ofelectronic components of the power source 5. These features are alsoavailable to the vent 41 in other embodiments.

In other embodiments, the first air inlet 2201 is projected onto the endsurface 44 in an axis of the LED lamp to occupy an area on the endsurface 44, which may be a first portion (first opening region 433). Theother area on the end surface 44 may be a second portion (second openingregion 434). The vent 41 in the first portion is smaller than the vent41 in the second portion in area. As a result, heat of the fins 11 canbe better dissipated to perform better heat dissipation to the LED chips311 and prevent a region around the LED chips 311 from forming hightemperature. In detail, area of both the first portion and the secondportion can be selected according to actual requirements.

In some applications, there may be a limit of overall weight of an LEDlamp. For example, when an LED lamp adopts an E39 head, its maximumweight limit is 1.7 Kg. Thus, besides the fundamental elements such as apower source, a lamp cover and a lamp shell, in some embodiments, weightof a heat sink is limited within 1.2 Kg. For some high-power LED lamps,the power is about 150 W˜300 W, and their luminous flux can reach 20000lumens to 45000 lumens. Under a limit of weight, a heat sink shoulddissipate heat from an LED lamp with 20000˜45000 lumens. Under acondition of heat dissipation of natural convection, usually power of 1W needs area of heat dissipation of at least 35 square cm. The followingembodiments intend to reduce area of heat dissipation for power of 1 Wunder guarantee of a receiving space of the power source 5 and effect ofheat dissipation. Under a precondition of weight limit of the heat sink1 and limit of the power source 5, the best effect of heat dissipationcan be accomplished.

As shown in FIGS. 1 and 2, in this embodiment, the LED lamp includespassive heat dissipating elements which adopt natural convection andradiation as a heat dissipating manner without any active heatdissipating elements such as a fan. The passive heat dissipating elementin this embodiment includes a heat sink 1 composed of fins 11 and a base13. The fins 11 radially extend from and connect to the base 13. Whenusing the LED lamp, at least part of heat from the LED chips 311 isconducted to the heat sink 1 by thermal conduction. At least part ofheat occurring from the heat sink 1 is transferred to external air bythermal convection and radiation. A diameter of a radial outline of theheat sink 1, in a hanging status as shown in the figures, tapers offupward or is substantially in a taper shape for a better match with alampshade. When the heat sink 1 in this embodiment is dissipating heat,at least part of heat is thermally radiated to air therearound toperform heat dissipation. An important factor of thermal radiation isemissivity. To improve emissivity of the heat sink 1, surfaces of theheat sink in this embodiment are specially treated. For example,surfaces of the heat sink 1 are provided with radiation heat-dissipatingpaint or electrophoretic coating to increase efficiency of thermalradiation and to rapidly dissipate heat of the heat sink 1. Anothersolution is forming a nanostructured porous alumina layer on thesurfaces of the fins 11 by anodization in an electrolyte to form a layerof nanostructured porous alumina. As a result, ability of heatdissipation of the fins 11 can be enhanced without adding the number ofthe fins 11. Alternatively, the surfaces of the fins 11 may be coatedwith an anti-thermal-radiation layer to reduce thermal radiation betweenthe fins 11. This can make more heat radiate to air. Theanti-thermal-radiation layer may adopt paint or oxide coating, in whichthe paint may be normal paint or radiation heat dissipation paint. Tofurther enhance heat dissipating effect of the heat sink 1. Preferably,it further contains aluminum such as a small or micro amount ofaluminum. Adopting both zinc and magnesium with the above percentagescan form MgZn₂ with a reinforcement effect. This makes a heat treatmenteffect of the heat sink 1 far better than a one zinc binary alloy.Tensile strength can be significantly increased. Both resistance tostress corrosion and flaking corrosion resistance also increases.Performance of thermal conduction also increases. In sum, performance ofheat dissipation of the heat sink 1 is better. In addition, the heatsink 1 may be made of a material with low thermal resistance/highthermal conductivity, such as an aluminum alloy. In some embodiments,the heat sink 1 can be made of an anodized 6061 T6 aluminum alloy withthermal conductivity k=167 W/m·k. and thermal emissivity e=0.7. In otherembodiments, other materials are available, such as a 6063 T6 or 1050aluminum alloy with thermal conductivity k=225 W/m·k. and thermalemissivity e=0.9. In other embodiments, other alloys are stillavailable, such as AL 1100, etc. In some embodiments, a die castingalloy with thermal conductivity is available. In other embodiments, theheat sink 1 may include other metals such as copper. FIG. 19a is across-sectional view of the heat sink 1 of an embodiment. As shown, insome embodiments, the heat sink 1 is added with a heat dissipatingpillar 12. In detail, the heat sink 1 includes a heat dissipating pillar12, fins 11 and a base 13. The heat dissipating pillar 12 connects tothe base 13. The fins 11 are radially disposed around the heatdissipating pillar 12. A root portion of the fins 11 connects to thebase 13 on a circle around the heat dissipating pillar 12. The heatdissipating pillar 12 supports the fins 11 to prevent the fins 11 frombeing skewed in machining. When using the LED lamp, the heat dissipatingpillar 12 or the base 13 transfers heat from the LED chips 311 to thefins 11. The heat dissipating pillar 12 is a hollow body with twoopening ends, for example, the heat dissipating pillar 12 may be ahollow cylinder. The heat dissipating pillar 12 may be made of amaterial which is the same as the heat sink 1. This material possessesgreat thermal conductivity, such as an alloy, to implement light weightand low cost. In other embodiments, the heat dissipating pillar 12 maybe made of copper to enhance thermal conductivity of the heat sink 1 andimplement rapid heat transfer. In other embodiments, an inner wall ofthe heat dissipating pillar 12 may be provided with a heat conductionlayer with a thickness of 0.1 mm˜0.5 mm to further improve an effect ofheat dissipation. Specific surface area of the fins 11 is 4˜10 times ofspecific surface area of the heat dissipating pillar 12, preferably, 6˜8times. FIG. 19b is a top view of an LED lamp using the heat sink of FIG.19a . As shown, when the LED lamp is a high-power lighting device, aninner diameter r of the bottom of the heat dissipating pillar 12 may be10˜15 mm. That is, a distance from the central axis XX of the heatdissipating pillar 12 to an inner surface of the heat dissipating pillar12 may be 10˜15 mm. Because the fins 11 radially extend from the heatdissipating pillar 12, a diameter R from the axis to an outer edges ofthe fins 11 may be greater than or equal to 15 mm and less than 20 mm.That is, a distance from the central axis of the heat sink 1 to an outeredges of the fins 11 may be greater than or equal to 15 mm and less than20 mm. From the bottom to the top of the heat sink 1, an inner diameterdefined by the fins 11 may be identical or different. In one example,length (R−r) extending from each fin 11 to the central axis XX of theheat sink 1 may be constant along a height direction of the heat sink 1or may vary along a height direction of the heat sink 1. Length of eachfin 11 extending from an inner surface of the heat sink 1 may beidentical or different. That is, length of the fins 11 may be identicalor different in length. Each fin 11 may extend from the inner surface ofthe heat sink 1 in a direction parallel to the central axis of the heatsink 1 or spirally extend from the inner surface of the heat sink 1.

As shown in FIGS. 2, 4 and 5, the base 13 of the heat sink 1 has a lowerend 133 located under the base 13, i.e. both the lower end 133 and thelight board 3 are located on the same side. In this embodiment, thelower end 133 protrudes from the light board 3 in an axis of the LEDlamp. In a using (hanging) status of the light board 3 being downward,the lower end 133 is lower than the light board 3 in position. As aresult, the position of the lower end 133 can protect the LED board 3.When collision occurs, the lower end 133 will collide first to preventthe light board 3 from colliding. As shown in FIGS. 2 and 4, in anotheraspect, the base 13 has a recess 132 in which the light board 3 isplaced. The recess 132 is of a cylindrical shape or a substantiallycylindrical shape, or a cylindrical platform structure. When the recess132 is of a cylindrical shape, a diameter of the cylinder is less thanthat of the base 13. The recess 132 in the base 13 is advantageous toreducing a glare effect of the LED lamp and improve direct vision andcomfort of users (inner walls of the recess 132 screen at least part oflateral light from the LED chips 311 to decrease glare). In someembodiments, the base 13 may have no recess. In some embodiments, tomake both the light board 3 and the heat sink 1 have maximum contactarea to guarantee a heat dissipation effect, a surface of the base 13 isa flat plane.

FIG. 20 is a cross-sectional view of an LED lamp of an embodimentwithout the lamp cover 4. As shown, in some embodiments, the lower end133 is configured to be slanted (relative to the horizon when the LEDlamp is being hung). When the slant is flat and straight in a radialdirection, an angle between the slant and the horizon is 3˜4 degrees. Inother embodiments, the angle is greater than 0 degrees but less than 6degrees. In some embodiments, when the slant is arced in a radialdirection, an angle between a tangent plane of the arced surface and thehorizon is 3˜4 degrees. In other embodiments, the angle is greater than0 degrees but less than 6 degrees. When the lower end 133 is inclined toa specific angle (e.g. an angle between the lower end 133 and the outerreflecting surface 4302 is 120˜180 degrees), it could serve as anextension of the outer reflecting surface 4302 to perform reflection.

FIG. 21 is a perspective view of an LED lamp of an embodiment of thepresent invention. As shown in FIGS. 2 and 21, another side of the base13 of the heat sink 1, which is opposite to the lower end 133, has aback side 134. An end of each fin 11 extends to connect with the backside 134. Thus, At least part of each fin 11 projects from the LED lightboard 3 in an axis. In one example, in an axial direction of the LEDlamp, each of the fins 11 is formed with an extension portion 1101between the back side 134 of the base 13 and the light board 3. Theextension portions 1101 can increase area of heat dissipation of thefins 11 and improve an effect of heat dissipation. In addition, theextension portion 1101 does not increase overall height of the LED lampso as to be advantageous to controlling overall height of the LED lamp.

FIG. 22 is a cross-sectional view of the LED lamp of this embodiment. Asshown, in this embodiment, the back side 134 of the base 13 is slanted.For example, when the LED lamp is being hung, in an inward radialdirection, the back side 134 is upwardly slanted. In another aspect, ina radial direction of the LED lamp toward an axis of the LED lamp, anaxial distance from the back side 134 to the light board 3 isprogressively increased. Such an arrangement is advantageous toconvection air is introduced along the back side 134 to bring out heatof the back side 134 and prevents the back side 134 from obstructing airflowing into.

As shown in FIGS. 2 and 5, in a using status, the light board 3 isdownwardly arranged, a position of the lower end 133 is lower than anend side 44 of the lamp cover 4 and the light output surface 43. As aresult, when packing, transporting or using the LED lamp, if collisionoccurs, then the lower end 133 will collide to prevent the lamp coverfrom colliding to damage the end side 44 or the light output surface 43.

As shown in FIGS. 2 and 5, a receiving space (indent 132) is encompassedby the lower ends 133 for receiving the lamp cover 4. Height of the lampcover 4 received in the receiving space does not project from the lowerend 133. Height of the LED lamp mainly includes height of the lamp shell2, height of the heat sink 1 and height of the lamp cover 4. In thisembodiment, the lamp cover 4 does not project from the lower end 133,this can control overall height of the lamp and the lamp cover 4 doesnot increase overall height of the lamp. In another aspect, the heatsink 1 additionally increases heat dissipating portion (downwardprotruding part of the light board 3 corresponding to the lower end133). In other embodiments, a part of the lamp cover 4 may project fromthe lower end 133.

As shown in FIGS. 2, 4 and 5, a gap is kept between the end side 44 andthe light board 3 to form a room 8. The room 8 communicates with boththe first air inlet 2201 of the first heat dissipating channel 7 a andthe second air inlet 1301 of the second heat dissipating channel 7 b.Air flows into the room 8 through the vent 41 of the end side 44 andthen flows into both the first heat dissipating channel 7 a and thesecond heat dissipating channel 7 b. The room 8 allows air therein tomix and the mixed air is distributed according to negative pressure(resulting from temperature difference) of both the first and secondheat dissipating channels 7 a, 7 b so as to make distribution of airmore reasonable.

In this embodiment, when a passive heat dissipation manner (fanless) isadopted, the ratio of power (W) of the LED lamp to heat dissipatingsurface area (square cm) of the heat sink 1 is 1:20˜30. That is, eachwatt needs heat dissipating surface area of 20˜30 square cm for heatdissipation. Preferably, the ratio of power of the LED lamp to heatdissipating surface area of the heat sink 1 is 1:22˜26. More preferably,the ratio of power of the LED lamp to heat dissipating surface area ofthe heat sink 1 is 1:25. The first heat dissipating channel 7 a isformed in the lamp shell 2, the first heat dissipating channel 7 a hasthe first air inlet 2201 at an end of the lamp shell 2, and another endof the lamp shell 2 has the venting hole 222. Air flows into the firstair inlet 2201 and flows out from the venting hole 222 to bring out heatin the first heat dissipating channel 7 a. The second heat dissipatingchannel 7 b is formed in the fins 11 and the base 13 and the second heatdissipating channel 7 b has the second air inlet 1301. Air flows intothe second air inlet 1301, passes the second heat dissipating channel 7b, and finally flows out from the spaces between the fins 11 to bringout heat radiated from the fins 11 to air therearound and enhance heatdissipation of the fins 11. By both the first and second heatdissipating channels 7 a, 7 b, efficiency of natural convection can beincreased. This reduces required area of heat dissipation of the heatsink 1 so as to make the ratio of power of the LED lamp to heatdissipating area of the heat sink 1 be between 20 and 30. In thisembodiment, overall weight of the LED lamp is less than 1.7 Kg. When theLED lamp is provided with power of about 200 W (below 300 W, preferably,below 250 W), the LED chips 311 are lit up and emit luminous flux of atleast 25000 lumens.

As shown in FIG. 1, weight of the heat sink 1 in this embodimentaccounts for above 50% of weight of the LED lamp. In some embodiments,weight of the heat sink 1 accounts for 55˜65% of weight of the LED lamp.Under this condition, volume of the heat sink 1 accounts for above 20%of volume of the overall LED lamp. Under a condition of the same thermalconductivity of the heat sink 1 (i.e. overall heat sink 1 uses a singlematerial or two different materials with almost identical thermalconductivity), the larger the volume occupied by the heat sink 1 is, thelarger the heat dissipating area which can be provided by the heat sink1 is. As a result, when volume of the heat sink 1 accounts for above 20%of volume of the overall LED lamp, the heat sink 1 may have more usablespace to increase its heat dissipating area. Considering the arrangementspace of the power source 5, the lamp cover 4 and the lamp shell 2,preferably, volume of the heat sink 1 accounts for 20%˜60% of volume ofthe overall LED lamp. More preferably, volume of the heat sink 1accounts for above 25˜50% of volume of the overall LED lamp.Accordingly, although the overall size of the LED lamp is limited andthe space for receiving the power source 5, the lamp cover 4 and thelamp shell 2 must be kept, volume of the heat sink 1 can still bemaximized. This is advantageous to design of overall heat dissipation ofthe LED lamp.

FIG. 23 is top view of the heat sink 1 of the LED lamp of an embodiment.As shown, the heat sink 1 suffers the above volume limit, so at leastpart of the fins 11 are extended outward in a radial direction of theLED lamp with at least two sheets at an interval. By such anarrangement, the fins 11 in a fixed space can have larger area of heatdissipation. In addition, the extended sheets form support to the fins11 to make the fins firmly supported on the base 13 to prevent the fins11 from deflecting.

In detail, as shown in FIG. 23, the fins include first fins 111 andsecond fins 112. The bottoms of both the first fins 111 and the secondfins 112 in an axis of the LED lamp connect to the base 13. The firstfins 111 interlace with the second fins 112 at regular intervals. Beingprojected from the axial direction of the LED lamp, each of the secondfins 112 is to be seen as a Y-shape. Such Y-shaped second fins 112 canhave more heat dissipating area under a condition of the heat sink 1occupying the same volume. In this embodiment, both the first fins 111and the second fins are evenly distributed on a circumference,respectively. Every adjacent two of the second fins 112 are symmetricalabout one of the first fins 111. In this embodiment, an interval betweenone of the first fins 111 and adjacent one of the second fins 112 is8˜12 mm. In general, to make air flow in the heat sink 1 smooth and tomake the heat sink perform a maximum effect of heat dissipation,intervals between the fins 11 should be as uniform as possible.

FIG. 27 is a main view of an LED lamp of another embodiment. As shown,the fins 11 are divided into two portions in a radial direction of theLED lamp. The first portion 111 a is less than the second portion 111 bin curvature (where the curvature means curvature on an outline of theLED lamp). In other embodiment, the first portion 111 a is greater thanor equal to the second portion 111 b in curvature.

FIG. 28 is a main view of an LED lamp of another embodiment. As shown,two sides of each fin 11 are provided with heat dissipating bars 16.Each of the heat dissipating bar 16 on a side is located betweenadjacent two of the heat dissipating bars on the other side. Forexample, the heat dissipating bars 16 on two opposite sides do notsuperpose each other in a projective direction. In this embodiment, adistance between every two of the heat dissipating bars on a side is thesame as a distance between every two of the heat dissipating bars on theother side. Such heat dissipating bars 16 can increase overall surfacearea of the fins 11 to make the fins 11 have more heat dissipating areafor heat dissipation for improving performance of heat dissipation ofthe heat sink 1. In this embodiment, to increase surface area of thefins 11, surfaces of the fins 11 may be configured to be of a wavedshape.

As shown in FIGS. 11 and 23, at least one of the fins 11 is divided intotwo portions in a radial direction of the LED lamp. Thus, a gap betweenthe two portions forms a passage to allow air to pass. In addition, theprojecting area of the gap directly exactly corresponds to an area thatthe LED chips 311 are positioned on the LED board 3 to enhanceconvection and improve an effect of heat dissipation to the LED chips311. In an aspect of limited overall weight of the LED lamp, part of thefins 11 divided with a gap reduces the amount of the fins 11, decreasesoverall weight of the heat sink 1, and provides a surplus space toaccommodate other elements. In this embodiment, as shown in FIG. 27, thefins 11 may have no above gap. That is, each of the fins 11 is a singlepiece in a radial direction.

FIG. 24 is an enlarged view of portion E in FIG. 23. As shown in FIGS.23 and 24, the fins 11 includes first fins 111 and second fins 112. Eachof the first fins 11 is divided into two portions in a radial directionof the LED lamp, i.e. a first portion 111 a and a second portion 111 b.The two portions are divided with a gap portion 111 c. The first portion111 a is located inside the second portion 111 b in a radial direction.Each of the second fins 112 has a third portion 112 a and a fourthportion 112 b extending therefrom. The fourth portions 112 b are locatedradially outside the third portions 112 a to increase space utilizationand make the fins have more heat dissipating are for heat dissipation.As shown in FIG. 24, the third portion 112 a is connected to the fourthportion 112 b through a transition portion 113. The transition portion113 has a buffer section 113 a and a guide section 113 b. At least oneor both of the buffer section 113 a and the guide section 113 b arearced in shape. In other embodiment, both the buffer section 113 a andthe guide section 113 b are formed into an S-shape or an invertedS-shape. The buffer section 113 a is configured to prevent air radiallyoutward flowing along the second fins 112 from being obstructed to causevortexes. Instead, the guide section 113 b is configured to be able toguide convection air to radially outward flow along the second fins 112without interference (as shown id FIG. 25).

As shown in FIG. 24, one of the second fins 112 includes a third portion112 a and two fourth portions 112 b. The two fourth portions 112 b aresymmetrical about the third portion 112 a. In other embodiments, one ofthe second fins 112 may include a third portion 112 a and multiplefourth portions 112 b such as three or four fourth portions 112 b (notshown). The multiple fourth portions 112 b of the second fin 112 arelocated between two first fins 111.

As shown in FIG. 24, a direction of any tangent of the guide section 113b is separate from the gap portion 111 c to prevent convection air fromflowing into the gap portion 111 c through the guide portion 113 b, suchthat the poor efficiency of heat dissipation caused by longer convectionpaths is able to be avoided as well. Preferably, a direction of anytangent of the guide section 113 b is located radially outside the gapportion 111 c. In other embodiments, a direction of any tangent of theguide section 113 b is located radially inside the gap portion 111 c.

As shown in FIG. 26, in another embodiment, a direction of any tangentof the guide section 113 b falls in the gap portion 111 c to makeconvection more sufficient but convection paths will increase.

As shown in FIG. 21, at least partially of fin 11 has a protrusion 1102projecting from a surface of the fin 11. The protrusions 1102 extendalong an axis of the LED lamp and are in contact with the base 13. Asurface of the protrusion 1102 may selectively adopt a cylindrical shapeor a regular or an irregular polygonal cylinder. The protrusions 1102increase surface area of the fins 11 to enhance efficiency of heatdissipation. In addition, the protrusions 1102 also form a supporteffect to the fins 11 to prevent the fins 11 from being inflected inmanufacture. In some embodiments, a single fin 11 is divided into twoportions in a radial direction of the LED lamp. Each portion is providedwith at least one protrusion 1102 to support the two portions. In thisembodiment, the protrusion 1102 is located at an end portion of each fin11 in a radial direction of the LED lamp, for example, at end portionsof the first portions 111 a, 111 b (the ends near the gap portion 111c).

In some embodiments, when each fin 11 is a single piece without the gapportion, the protrusion 1102 may also be disposed on a surface of eachfin 11 (not shown) to increase surface area of heat dissipation of thefins 11 and have a support effect to the fins 11 to prevent the fins 11from being inflected in manufacture.

FIG. 29 is a bottom view of the LED lamp of FIG. 1 without the lampcover 4. FIG. 30 is an enlarged view of portion A in FIG. 29. As shownin FIGS. 29 and 30, the heat sink 1 is disposed outwardly of the sleeve21, and the power source 5 is disposed in the inner space of the sleeve21. A distance is kept between distal ends of the fins 11 and the sleeve21. Accordingly, the sleeve 21 which has been heated to be thermallyexpanded will not be pressed by the fins 11 to be damaged. Also, heatfrom the fins 11 will not be directly conducted to the sleeve 21 toadversely affect electronic components of the power source 5 in thesleeve 21. Finally, air existing in the distance between the fins 11 andthe sleeve 21 of the lamp shell 2 (as shown in FIG. 3) possesses aneffect of thermal isolation so as to further prevent heat of the heatsink 1 from affecting the power source 5 in the sleeve 21. In otherembodiments, to make the fins 11 have radial support to the sleeve 21,distal ends of the fins 11 may be in contact with an outer surface ofthe sleeve 21 and another part of the fins 11 are not in contact withthe sleeve 21. Such a design may be applied in the LED lamp shown inFIG. 29. As shown in FIG. 29, the light board 3 includes a thirdaperture 32 for exposing both the first air inlet 2201 of the first heatdissipating channel 7 a and the second air inlet 1301 of the second heatdissipating channel 7 b. In some embodiments, to rapidly dissipate heatfrom the power source 5, the ratio of cross-sectional area of the firstair inlet 2201 to cross-sectional area of the second air inlet 1301 isgreater than 1 but less than or equal to 2. In some embodiments, torapidly dissipate heat from the power source 5, the ratio ofcross-sectional area of the second air inlet 1301 to cross-sectionalarea of the first air inlet 2201 is greater than 1 but less than orequal to 1.5.

As shown in FIGS. 21 and 22, the innermost of the fins 11 in a radialdirection of the LED lamp is located outside the venting hole 222 in aradial direction of the LED lamp. In one example, an interval is keptbetween the innermost of the fins 11 in a radial direction of the LEDlamp and the venting hole 222 in a radial direction of the LED lamp. Asa result, heat from the fins 11 flowing upward will not gather to theventing hole 222 to keep an interval with the venting hole 222. Thisavoids heat making air around the venting hole 222 heat up to affectconvection temperature speed of the first heat dissipating channel 7 a(the convection speed depends upon a temperature difference between twosides of the first heat dissipating channel 7 a, when air temperaturenear the venting hole 222 rises, the convection speed willcorrespondingly slow-down.).

FIG. 31 is a cross-sectional view of an LED lamp of an embodiment. FIG.32 is an enlarged view of the LED lamp of portion C in FIG. 31. Asshown, the heat sink 1 includes the fins 11 and the base 13. The base 13has a projecting portion 135 which is downwardly formed in an axialdirection of the LED lamp. The projecting portion 135 protrudes from thelight board 3 in an axial direction of the LED lamp. The lowermostposition of the projecting portion 135 (lower end 133) is substantiallyflush with the light output surface 43 of the light cover 4 (in an axialdirection of the LED lamp) or the lowermost position of the projectingportion 135 slightly protrudes from the light output surface 43. Forexample, the lowermost position of the projecting portion 135 protrudesfrom the light output surface 43 by about 1˜10 mm to keep overall heightof the heat sink 1 in the LED lamp unvarying or slightly increase volumefor obtaining more heat dissipating area of both the fins 11 and thebase 13.

The projecting portion 135 in this embodiment is configured to beannular and a concave structure is defined by both the projectingportion 135 and the base 13 for receiving and protecting both the lightsource and the light cover 4. Also, the concave structure can perform aneffect of anti-flare (because the concave structure shades lateral lightfrom the light source).

As shown in FIG. 32, the base 13 has a first inner surface 136 and thelamp cover 4 has a peripheral wall 45. When the lamp cover 4 has beencorrectly installed to the LED lamp, the first inner surface 136corresponds to the peripheral wall 45 (the outer wall of the lamp cover4). A gap is kept between the first inner surface 136 and the peripheralwall 45 to prevent the lamp cover 4 from thermally expanding and beingpressed by the first inner surface 136 to be damaged. The gap betweenthe first inner surface 136 and the peripheral wall 45 can reduce oravoid the abovementioned pressing. In other embodiments, a part of theperipheral wall 45 is in contact with the first inner surface 136 toradially support the lamp cover 4 by the first inner surface 136. Gapsare still kept between the other parts of the peripheral wall 45 and thefirst inner surface 136.

As shown in FIG. 32, the first inner surface 136 is configured to be aslant and an angle is formed between the first inner surface 136 and thelight board 3. The angle may be an obtuse angle. Thus, when the lampcover 4 is thermally expanded and its peripheral wall 45 presses theslant, the pressure exerted from the first inner surface 136 to an outerportion of the lamp cover 4 is divided into a downward component and ahorizontal component to reduce horizontal pressure to the lamp cover 4(horizontal pressure is a main cause of damage). In other embodiments,the peripheral wall 45 may abut against the first inner surface 136 (notshown) so as to support or limit the lamp cover 4. Also, because thefirst inner surface 136 is a slant, damage of the lamp cover 4 resultingfrom pressure of thermal expansion can be decreased. An end portion ofthe peripheral wall 45 may abut against the first inner surface 136 todecrease contact area between overall peripheral wall 45 and the base 13and avoid excessive thermal conduction.

As shown in FIG. 32, the base further includes a second inner surface137 and the lamp cover 4 has a peripheral wall 45. A gap is kept betweenthe peripheral wall 45 and the first inner surface 136. An end portionof the peripheral wall 45 abuts against the second inner surface 137. Anangle between the first inner surface 136 and the light board 3 is lessthan an angle between the second inner surface 137 and the light board3. That is, the second inner surface 137 is flatter than the first innersurface 136. As a result, when the peripheral wall 45 abuts against thesecond inner surface 137 and the lamp cover 4 is thermally expanded, thehorizontal pressure from the second inner surface 137 to the lamp cover4 becomes less. In this embodiment, the angle between the second innersurface 137 and the light board 3 is between 120 degrees and 150degrees. If the angle is too big, then radial support to the lamp cover4 in a radial direction of the LED lamp will not be sufficient enough.While if the angle is too small, not only can the horizontal pressureexerted to the lamp cover 4 which has been thermally expanded not bereduced, but also limiting and supporting the lamp cover 4 in an axialdirection of the LED lamp cannot be obtained. When the angle falls inthe above range, a great balance can be accomplished. In otherembodiments, both the second inner surface 137 and the first innersurface 136 may be curved. A distance difference between the secondinner surface 137 and the axis of the LED lamp and between the firstinner surface 136 and the axis of the LED lamp downward progressivelyincreases. However, in general, the second inner surface 137 is flatterthan the first inner surface 136.

As shown in FIG. 33, the end portion of the peripheral wall 45 isprovided with protruding plates 451 upward extending from the peripheralwall 45 at regular intervals. The protruding plates 451 are the partsthat the end portion of the peripheral wall 45 is in actual contact withthe second inner surface 137. The protruding plates 451 can reducecontact area between the peripheral wall 45 and the base 13 to preventheat of the heat sink 1 from being conducted to the lamp cover 4 to makethe lamp cover 4 overheat.

As shown in FIGS. 31 and 32, a gap is formed between the peripheral wall45 and the base 13 and the base 13 is formed with a hole. A side of thehole communicates with the gap and the other side corresponds to thefins 11. In one example, air may flow into the gap, passes the hole andreaches the fins 11 to enhance convection. The convection path as shownby the arrow in FIG. 32 may form a fourth heat dissipating channel 7 dof the LED lamp in this embodiment. Because the protruding plates 451are arranged on the peripheral wall 45 at regular intervals, air canpass through intervals between the protruding plates 451 (as shown inFIG. 33) to accomplish the abovementioned convection. As shown in FIGS.34 and 35, in another embodiment, the fourth heat dissipating channel 7d may also be disposed at other positions as long as a region between alower portion of the LED lamp and the fins 11 are communicated. Forexample, a through hole 315 is formed between adjacent two LED chip sets31. At this time, the lamp cover 4 may be configured to be separate,i.e. include multiple parts to separately cover different LED chip sets31. The through hole 315 is located between two parts of the lamp cover4 to make the through hole 315 communicate with the lower portion of theLED lamp and communicate with the spaces between the fins 11.

The heat sink 1 in this embodiment is an integrated structure so as toadvantageous to reducing thermal resistance between the fins 11 and thebase 13. In other embodiments, in order to be convenient to be machinedand formed, the fins 11 and the base 13 may also be configured to bedetachable.

In this embodiment, different positions of the fins 11 have differenttemperature. For example, when the LED lamp is working, a portion nearthe LED chips 311 is around 80° C., but the temperature of the upperportion (the opposite portion to the portion near the LED chips 311) ofthe fins 11 would slightly decrease. With different distribution oftemperature inside the fins 11, the heat dissipation efficiency of thefin 11 is defined as a percentage of the post-dissipation temperature tothe average temperature of the fins 11. The heat dissipation efficiencyof the fins 11 can be calculated by thermal conductivity and size. Theheat dissipation efficiency of the fins 11 is relative with thermalconductivity, thickness, width and height of the fins 11.

In this embodiment, to improve heat dissipation efficiency of the fins11, thickness of each fin 11 is configured to be 0.8˜2 mm, preferably,1˜1.5 mm. The ratio of thickness to length of the fin 11 is not lessthan 1:80. Preferably, the ratio of thickness to length of the fin 11 isnot less than 1:70. More preferably, the ratio of thickness to length ofthe fin 11 is not less than 1:60˜80. According to the effect of heatdissipation of the fins 11, a balance can be obtained between overallweight of the heat sink 1 and heat dissipating area to make the finshave better efficiency. The length of the fin 11 means height in anaxial direction of the LED lamp. The ratio of width to length of the fin11 in this embodiment is configured to be greater than 1:1.5,preferably, the ratio is greater than 1:1.3 to make thermal conductivityof the fins 11 better and improve efficiency of the fins 11. The lengthof the fin 11 means height in an axial direction of the LED lamp, andthe width means length of the fin 11 in a radial direction of the ELDlamp. When the fins 11 are in irregular directions, width of the fins 11may use their average value or a sum of a half of the maximum value ofwidth and a half of the minimum value of width, and length of the fins11 may use their average value or a sum of a half of the maximum valueof length and a half of the minimum value of length.

$H = {3.86 \times \sqrt{\frac{V}{L}}}$

where H stands for thermal conductivity, its unit is W/(m²·° C.);

V stands for flowing speed of convection air; and

L stands for length of the fin in the convection direction.

It can be seen from the above formula that thermal conductivity isaffected by arrangement of heat dissipating surface of the fins 11 muchmore than other factors when considering at least part of heat of thefins 11 which is dissipated by convection. In addition, when the fins 11are transferring heat, their thickness (cross-sectional area) is animportant factor, too. Temperature of downward flowing air would riseand its cooling ability correspondingly decreases. Thus, under the fins11 with the same area, if the fins 11 are configured to have shorterlength and longer width in the airflow direction, then the amount ofheat dissipation would increase. Besides, under the same heatdissipating area, the above embodiment may control height of the fins 11to make the fins 11 have more area near the LED chips 311 and enhancethermal conduction from the LED chips 311 to the fins 11. Thickness ofthe fin 11 may also affect efficiency of the fins 11. The larger thethickness of the fin 11 is, the higher the efficiency is, but a balanceof weight and heat dissipating area should also be considered. In sum,the ratio of thickness to length of the fin 11 is configured to be notless than 1:80, and the ratio of width to length of the fin 11 isconfigured to be greater than 1:1.5.

FIGS. 36a ˜36 m are schematic views of some embodiments of the heat sink10, which can be applied in LED lamps to replace the heat sink 1 shownin FIG. 1.

As shown in FIG. 36a , which shows a first embodiment of the heat sink10. The heat sink 10 includes first fins 101 and second fins 102. Theheat sink 10 is defined with a first circumference R1 and a secondcircumference R2, which are projected onto the base 130. The firstcircumference R1 is less than the second circumference R2. On the base130, the first fins 101 extend into a cylindrical room (the part forreceiving the sleeve 21, the cylindrical room mentioned in the followingembodiments is the same as this) but do not exceed the secondcircumference R2. For example, the first fins 101 extend from thecylindrical room right to the first circumference R1. The second fins102 extend to the first circumference R1 but do not exceed the secondcircumference R2, e.g. just extend to the second circumference R2. In aradial direction, both the first fins 101 and the second fins 102 areinterlacedly arranged. Each adjacent of the second fins 102 issymmetrically arranged about one of the first fins 101. Intervals areformed between adjacent two of the first fins 101 and the second fins102 for allowing air to pass and prolonging paths that air flows throughthe first and second fins 101, 102 to increase the amount of heatexchange between the fins 101, 102 and the airflow.

As shown in FIG. 36 b, which shows a second embodiment of the heat sink10. The heat sink in this embodiment differs from the first embodimentby the heat sink 10 further including division fins 108. The divisionfins 108 radially extend from an outer surface of the cylindrical roomto the second circumference R2. The division fins 108 are interlacedlyarranged with the first fins 101 within the first circumference R1 andare interlacedly arranged with the second fins 102 between the firstcircumference R1 and the second circumference R2. As a result, each ofthe division fins 108 is symmetrically between two of the first fins 101and two of the second fins 102.

As shown in FIG. 36 c, which shows a third embodiment of the heat sink10. The heat sink in this embodiment differs from the second embodimentby the heat sink 10 further including third fins 103. A thirdcircumference R3 is defined by being projected onto the base 103 of theheat sink 10. And the third circumference R3 is greater than the secondcircumference R2. On the base 103, the first fins 101 extend from thecylindrical room to the first circumference R1, the second fins 102extend from the first circumference R1 to the second circumference R2,and the third fins 103 extend from the second circumference R2 to thethird circumference R3. In a radial direction, the second fins 102 andthe third fins 103 are interlacedly arranged. Each two third fins 103are symmetrically arranged about one of the second fins 102.

The fins of the third embodiment may be further expanded to the nth fin,where n is an integer greater than two. For example, the firstcircumference R1 through the nth circumference with gradually gettingbigger are defined on the base 130. The first fins 101 extend from thecylindrical room to the first circumference R1. The nth fin extends fromthe (n−1)th circumference to the nth circumference. In a radialdirection, the (n−1)th fin and the nth fin are interlacedly arranged.Each two nth fins are symmetrically arranged about one of the (n−1)thfins. In addition, from first fin 101 to the nth fin, at least partthereof overlap with the light board 3 (a projection in an axialdirection of the LED board 3) to ensure a direct thermal conduction pathexisting between the LED light board 3 and the fins.

As shown in FIG. 36c , the nth fin and the (n−1)th fin are interlacedbut do not overlap. An outer edge of the (n−1)th fin does not exceed the(n−1)th circumference. The nth fin extends from the (n−1)thcircumference. For example, an outer edge of the second fin 102 does notexceed the second circumference R2, and the third fin 103 extends fromthe second circumference R2 and does not exceed the third circumferenceR3.

As shown in FIG. 36d , in the fins of the third embodiment, the nth finand the (n−1)th fin may interlacedly overlap. An outer edge of the(n−1)th fin exceeds the (n−1)th circumference but does not reach the nthcircumference. The nth fin extends from the (n−1)th circumference. Forexample, an outer edge of the second fin 12 exceeds the secondcircumference but does not reach the third circumference R3. The thirdfin 13 extends from the second circumference R2.

In the embodiment shown in FIGS. 1 and 2, an outer edge of each fin 11is arced. In other embodiments, an outer edge of the fin may be waved,straight or stepped.

As shown in FIG. 36 e, which shows a fourth embodiment of the heat sink10. The fourth embodiment differs from FIG. 1 by the fins of the heatsink 1. For example, an outer edge of the first fin 101 is perpendicularto the base 130. Thus, observing the first fins 101 from a viewpoint ina direction perpendicular to the axis, the fins present rectangular orsquare instead of upward tapered curved outer edges. The rectangularfirst fins 101, under the limit of the same height and width, caneffectively increase area of the first fins 101 and enhance thermalexchange with airflow.

As shown in FIG. 36f , in a specific embodiment, the fins of the heatsink 1 include the first fin 101 through the nth fin. Each of the firstfin through the nth fin has holes 101 a penetrating through two sides ofthe fin. For example, the first fin shown in FIG. 36f has the holes 101a through two sides thereof. The holes 101 a through two sides if thefin can promote air to flow to enhance heat dissipation and reduceweight of the heat sink 1.

As shown in FIG. 36g , in a specific embodiment, the fins of the heatsink 10 include the first fin 101 through the nth fin. They areconfigured to have a two-stage step. The first stage 1011 extends fromthe base 130 and the second stage 1012 extends from the first stage1011. Length of the first stage 1011 in a radial direction of the LEDlamp is greater than that of the second stage 1012 in a radial directionof the LED lamp. Height of the first stage 1011 in an axial direction ofthe LED lamp is lower than that of the second stage 1012 in an axialdirection of the LED lamp. Thus, observing the first fins 101 from aviewpoint in a direction perpendicular to the axis, the fins presentstepped. Such a shape guarantees fin area in the lower portion, which issufficient to conduct heat from the working LED chips 311. The upperportion uses both radiation and convection. As a result, fin area can beproperly reduced to decrease weight.

As shown in FIG. 36h , which shows a fifth embodiment of the heat sink10. The heat sink 10 of the fifth embodiment is based on the fourthembodiment. It further includes second fins 102. An outer edge of thesecond fin 102 is perpendicular to the base 130 to make the second finpresent rectangular or square. In addition, height of the second fin 102on the base 130 is less than height of the first fin 101 and the secondfins 102 interlace with the first fins 101. Thus, the second fins 102can increase area of thermal exchange with airflow. However, because itsheight is short, thermal radiation exchange between the first fins 101and the second fins 102 can be reduced. In this embodiment, if the totalamount of both the first fins 101 and the second fins 102 is the same asthe amount of the fins on the fourth embodiment (i.e. under thecondition of the same amount), then this embodiment is more advantageousto overall weight reduction of the heat sink 10 and can decrease thermalradiation exchange between the first fins 101 and the second fins 102.

As shown in FIG. 36 i, which shows the sixth embodiment of the heat sink10. The heat sink 10 of the sixth embodiment is based on the aboveembodiment. It further includes an outer support wall 106 and an innersupport wall 105. The outer support wall 106 connects to an outer edgeof the first fins 101 and the inner support wall 105 connects to aninner edge of the first fins 101 to prevent the first fins 101 frominflecting. As shown in FIG. 36i , observing the heat sink 10 from anupper viewpoint, both the outer support wall 106 and the inner supportwall 105 present annular to make the first fin 101 radially connected.Both the outer support wall 106 and the inner support wall 105 mayconnect to the base 130 or perpendicularly extend from an upper surfaceof the base 130. Both the outer support wall 106 and the inner supportwall 105 may also merely connect to the first fins 101 and keep adistance with the outer surface of the base 130. In an axial direction,height of both the outer support wall 106 and the inner support wall 105is less than height of the first fins 11 to maintain smooth axialairflow. Either of the outer support wall 106 and the inner support wall105 may be selected to be used. It is unnecessary to use both the outersupport wall 106 and the inner support wall 105. As shown in FIG. 36j ,both the outer support wall 106 and the inner support wall 105 may beconfigured to be segmentalized, i.e. the outer support wall 106 as anexample, it is divided into multiple arced segments 1061 at regular orirregular intervals on a single circumference. Each arced segment 1061connects at least two first fins 101 to further reduce adverse influenceto convection.

As shown in FIG. 36k , which shows a seventh embodiment of the heat sink10. The heat sink 10 of the seventh embodiment is based on the aboveembodiment to modify a shape of the first fins 101. In the seventhembodiment, the first fins 101 includes a first portion 101 a, a secondportion 101 b and a connecting portion 101 c. Both the first portion 101a and the second portion 101 b radially extend to connect to each otherthrough the connecting portion 101 c. The first portion 101 a extendsfrom an outer surface of the cylindrical room. The second portion 101 bconnects to the first portion 101 a through the connecting portion 101 cto further extend outward. The connecting portion 101 c is not parallelto the radial direction. In one embodiment, the connecting portion 101 cextends approximately along a circumferential direction or a directionperpendicular to a radial direction to make the first portion 101 a andthe second portion 101 b are interlaced arranged in a radial directionwithout being located on a radial extending line. The connecting portion101 c can increase area of the first fins 11 to improve thermal exchangeamount between airflow and the first fins 11. In addition, theconnecting portion 101 c also prevent the first fins from beinginflected.

As shown in FIGS. 36l and 36 m, which shows an eighth embodiment of theheat sink 10. The heat sink 10 of the eighth embodiment is based on theabove embodiment to modify a shape of the first fins 101. In the eighthembodiment, multiple concentric circles are defined on the base 130 andthe concentric circles perpendicularly extend from the base 130.

In FIG. 36 l, each of the first fins 101 on a corresponding one of theconcentric circles is continuous, i.e. the first fins 101 presentcontinuously annular. Each concentric circle is disposed with one firstfin 101.

In FIG. 36m , each of the first fins 101 on a corresponding one of theconcentric circles is discontinuous, i.e. the first fins 101 presentdiscontinuously annular. A gap is retained between two adjacent segmentsof the first fin 101 on the same concentric circle to allow air to flowradially.

In some embodiments, the heat sink has a central axis XX. A plane A-Awith the central axis XX as a normal and the central axis XX intersectat an intersection 91 in the cylindrical room of the heat sink. In someembodiments, the distance from the central axis XX to edges of the fins11 along the plane A-A is greater than zero as shown in FIGS. 37a-37d ,In FIG. 37a , the intersection 91 serves as a center, distance D1 as aradius, create a virtual circle on the plane A-A (the broken line shownin FIG. 37a ). The heat sink 1 has at least one fin 11. The virtualcircle abuts against an edge of the fin 11. When the heat sink 1 has aplurality if fins 11, a constant distance D1 exists from edges of thefins 11 to the central axis XX of the heat sink 1. The virtual circleabuts against edges of all the fins 11. In some embodiments, the heatsink 1 has multiple fins 11. The distances D1 and D2 from edges of atleast two of the fins 11 to the central axis XX of the heat sink 1 aredifferent. Distance D1 is less than distance D2. The intersection 91serves as a center, the shorter distance D1 as a radius, create avirtual circle on the plane A-A (the broken line shown in FIG. 37b ).The virtual circle does not abut against edges of the fins 11 with thedistance D2 as shown in FIG. 37 b.

In some embodiments, the heat sink 1 has multiple fins 11. All distancesD1, D2, D3 . . . Dn (only D1-D3 are shown in FIG. 37c ) from edges ofthe fins 11 to the central axis XX are different. Distance D1 is lessthan distance D2 which is less than distance D3. The intersection 91serves as a center, the shortest distance D1 as a radius, create avirtual circle on the plane A-A (the broken line shown in FIG. 37c ).The virtual circle does not abut against edges of the fins 11 which aregreater than the shortest distance D1 as shown in FIG. 37 c.

In some embodiments, the heat sink 1 has multiple fins 11. All distancesD1, D2, D3 from edges of the fins 11 to the central axis XX aredifferent. Distance D1 is less than distance D2 which is less thandistance D3. The intersection 91 serves as a center, distances D1, D2,D3 as radiuses, create three virtual circles on the plane A-A (thebroken line shown in FIG. 37d ). Part of the virtual circles do not abutagainst parts of edges of the fins 11. Part of the virtual circles passthrough parts of the fins 11 as shown in FIG. 37d . The virtual circlecreated on the plane A-A with distance D1 as a radius does not abutagainst the fins with distances greater than distance Dl. The virtualcircle created on the plane A-A with distance D2 as a radius, the fins11 with a passing distance less than D2 do not abut against the finswith distances greater than D2.

FIGS. 38a ˜38 i are top views of some embodiments of the heat sink 1,which replace the heat sink 1 in FIG. 1 for detailed description. Asshown in FIGS. 1 and 38 a, the heat sink 1 includes heat dissipatingunits and a base 13. Each heat dissipating unit extends from the base 13along an axial direction of the LED lamp. A specific embodiment of theheat dissipating units are fins 11. The heat dissipating units areradially arranged on the base 13. A root of each heat dissipating unitis connected to the base 13. A cylindrical room 14 is defined by inneredges of the heat dissipating units. The room 14 is used for receivingthe sleeve 21. When the LED lamp is working, heat from the light board 3is conducted by the base 13 to the heat dissipating units and finallyfrom the heat dissipating units to external air to enhance heatdissipation. The lamp shell 1 connects to the heat sink 1 andapproximately connects to upper edges of the heat dissipating units.Portions at least near the axis of the LED lamp of upper edges of theheat dissipating units are flatly cut off along a radial direction todefine a flat connecting plane. A corresponding fastener can be arrangedbetween the lamp shell 2 and upper edges of the heat dissipating unitsto fasten a lower end of the lamp shell 2 to the connecting plane toconnect the heat sink 1.

As shown in FIGS. 1, 2 and 38 a, a first cross-section A1 is defined onthe connecting plane along a radial direction of the LED lamp. A secondcross-section A2 is defined on a connecting surface between the heatsink 1 and the light board 3 along a radial direction of the LED lamp.In an embodiment, the amount of the heat dissipating units beingprojected onto the first cross-section A1 in an axial direction of theLED lamp is less than the amount of the heat dissipating units beingprojected onto the second cross-section A2 in an axial direction of theLED lamp. That is, in an axial direction, because air flows upward, theheat dissipating units should be prevented from being obstructed by thelamp shell 2 as much as possible. This makes upper edges of most heatdissipating units exposed to air to form heat dissipating channels whichare not obstructed by the lamp shell 2 for improving convection effectof the heat dissipating units. In another aspect, by means of the amountof the heat dissipating units being projected onto the firstcross-section A1 in an axial direction of the LED lamp being less thanthe amount of the heat dissipating units being projected onto the secondcross-section A2 in an axial direction of the LED lamp can accomplishthe above technical effect. In an aspect of area of axial projection ofthe heat dissipating units, by means of the amount of the heatdissipating units being projected onto the first cross-section A1 in anaxial direction of the LED lamp being less than the amount of the heatdissipating units being projected onto the outside of the firstcross-section A1 in an axial direction of the LED lamp can accomplishthe above technical effect.

As shown in FIG. 38 a, multiple annular zones are defined on the heatsink 1. Each annular zone owns different amount of the heat dissipatingunits from the others'. For example, the amount of the heat dissipatingunits owned by an inner annular zone is less than the amount of the heatdissipating units owned by an outer annular zone. The amount or area ofthe annular zones overlapping with the projection of the firstcross-section A1 in an axial direction of the LED lamp is less than theamount or area of the annular zones overlapping with the projection ofthe second cross-section A2 in an axial direction of the LED lamp.

In detail, as shown in FIG. 38b , the heat dissipating units may includemultiple first heat dissipating units 15 and multiple second heatdissipating units 16 (where both the first heat dissipating units 15 andthe second heat dissipating units 16 are different from both the firstfins 111 and the second fins 112 in FIGS. 23 and 24 in naming principleand category). In FIG. 38b , the first heat dissipating units 15 areradially inner fins and the second heat dissipating units 16 areradially outer fins. The first heat dissipating units 15 are mainlyprojected onto inner annular zones and the second heat dissipating units16 are mainly projected onto outer annular zones. An outer edge of eachfirst heat dissipating units 15 radially branches away into two secondheat dissipating units 16 (the first heat dissipating units 15 and thesecond heat dissipating units 16 may be continued or discontinued, thelatter means a radial gap is retained between the first heat dissipatingunits 15 and the second heat dissipating units 16) to make the secondheat dissipating units 16 is greater than the first heat dissipatingunits 15 in number. In addition, the first cross-section A1 is projectedonto inner annular zones and the second cross-section A2 is projectedonto outer annular zones, so the first heat dissipating units 15 isprojected onto inner annular zones in an axial direction of the LED lampand the second heat dissipating units 16 is projected onto outer annularzones in an axial direction of the LED lamp. As a result, the amount orarea of the first heat dissipating units 15 being projected onto thefirst cross-section A1 in an axial direction of the LED lamp is lessthan the amount or area of the second heat dissipating units 16 beingprojected onto the second cross-section A2 in an axial direction of theLED lamp.

As shown in FIGS. 38c and 38d , when the first heat dissipating units 15is greater than the second heat dissipating unit 16 in thickness,because of radial arrangement, a distance between adjacent two of thefirst heat dissipating units 15 near the axial axis of the LED lamp isless than a distance between adjacent two of the second heat dissipatingunits 16 away from the axial axis of the LED lamp. When thickness of thefirst and second heat dissipating unit 15, 16 is properly configured,any circumferential perimeter (sum of ΔX1) of the first cross-section A1of the first heat dissipating unit 15 is equal to any circumferentialperimeter (sum of ΔX2) of the second cross-section A2 of the second heatdissipating unit 16. The circumferential perimeter means a total lengthof arcs of any virtual circles with the axis of the LED lamp as a centercutting the first heat dissipating units 15 or the second heatdissipating units 16.

In detail, both the first and second heat dissipating units 15, 16 arefins which are radially distributed in the heat sink 1. The heat sink 1is outward divided into a first annular zone C1 and a second annularzone C2. The heat sink 1 further includes a cylindrical room 14 insidethe first annular zone C1. The cylindrical room 14 is mainly used forreceiving part of the power source board and providing a heatdissipating channel. A virtual circle with the axis of the heat sink 1as the center is created. When the sum of arcs which are formed by thevirtual circle falling in the first annular zone C1 to cut the fins isX1 (sum of ΔX1), and the sum of arcs which are formed by the virtualcircle falling in the second annular zone C2 to cut the fins is X2 (sumof ΔX2), then X1<X2. The ratio of the sum of arcs which are formed bythe virtual circle to cut the fins to the circumferential perimeter ofthe virtual circle may be 06˜0.2. This makes the fins have sufficientcross-sectional area to perform thermal conduction and maintaindistances between the fins to keep sufficient sizes of convectionchannels. Also, surface area of the fins is sufficient enough under thesame weight.

Furthermore, if the fins in the first annular zone C1 needs largercross-sectional area to perform thermal conduction, for example, densityof the LED chips 311 of the LED board 3 projected onto the first annularzone C1 is greater than density of projection on the second annular zoneC2 (where the term “density” means the number of the LED chips 311 inunit area of the annular zone), and the ratios of X1 and X2 to theperimeter of the virtual circle are Ra1 and Ra2, respectively, then itcan be configured that Ra1>Ra2 or X1>X2 to make the fins in the firstannular zone C1 have larger cross-sectional area to perform thermalconduction and maintain distances between the fins to keep sufficientsizes of convection channels.

Contrarily, if the fins in the second annular zone C2 needs largercross-sectional area to perform thermal conduction, for example, densityof the LED chips 311 of the LED board 3 projected onto the first annularzone C1 is greater than density of projection on the second annular zoneC2, and the ratios of X1 and X2 to the perimeter of the virtual circleare Ra1 and Ra2, respectively, then it can be configured that Ra1<Ra2 orX1<X2 to make the fins in the second annular zone C2 have largercross-sectional area to perform thermal conduction and maintaindistances between the fins in the first annular zone C1 to keepsufficient sizes of convection channels.

If density of the LED chips 311 of the LED board 3 projected onto thefirst annular zone C1 is equal to density of projection on the secondannular zone C2, then it can be configured that Ra1=Ra2 or X1=X2 to makethe fins in the first annular zone C1 is similar to the second annularzone C2 in efficiency of thermal conduction to avoid high temperaturedifference in the light board 3.

As shown in FIG. 38 e, in some embodiments, outer edges of merely somefirst heat dissipating units 15 radially branch away into two secondheat dissipating units 16 or the first heat dissipating units 15 and thesecond heat dissipating units 16 are individually disposed withdifferent distribution density. The heat sink 1 in FIG. 38f , the amountor area of the first heat dissipating units 15 being projected onto thefirst cross-section A1 in an axial direction of the LED lamp is greaterthan the amount or area of the second heat dissipating units 16 beingprojected onto the second cross-section A2 in an axial direction of theLED lamp. Identically, in a condition of multiple annular zones, theamount or area of the first heat dissipating units 15 being projectedonto inner annular zones in an axial direction of the LED lamp would begreater than the amount or area of the second heat dissipating units 16being projected onto outer annular zones in an axial direction of theLED lamp.

Identically, in FIG. 38f , when the first heat dissipating units 15 isless than the second heat dissipating units 16 in thickness, theinterval between adjacent two of the first heat dissipating units 15 maybe greater than the interval between adjacent two of the second heatdissipating units 16. When thickness of the first and second heatdissipating units 15, 16 is properly configured, any circumferentialperimeter of the first cross-section A1 of the first heat dissipatingunits 15 is equal to any circumferential perimeter of the secondcross-section A2 of the second heat dissipating units 16.

As shown in FIG. 38f , in one embodiment, outer edges of merely somefirst heat dissipating units 15 radially branch away into two secondheat dissipating units 16 or the first heat dissipating units 15 and thesecond heat dissipating units 16 are individually disposed withone-to-one correspondence in a single radial line to make the amount ofthe first heat dissipating units 15 being projected onto the firstcross-section A1 in an axial direction of the LED lamp be equal to theamount of the second heat dissipating units 16 being projected onto thesecond cross-section A2 in an axial direction of the LED lamp.Identically, in a condition of two or more annular zones, the amount orarea of the first heat dissipating units 15 being projected onto innerannular zones in an axial direction of the LED lamp would be equal tothe amount or area of the second heat dissipating units 16 beingprojected onto outer annular zones in an axial direction of the LEDlamp.

As shown in FIG. 38f , in one embodiment, when the first heatdissipating units 15 are equal to the second heat dissipating units 16in thickness, and the interval between adjacent two of the first heatdissipating units 15 is equal to the interval between adjacent two ofthe second heat dissipating units 16, any circumferential perimeter ofthe first cross-section A1 of the first heat dissipating units 15 isequal to any circumferential perimeter of the second cross-section A2 ofthe second heat dissipating units 16.

As shown in FIGS. 38a and 38g , the amount of the annular zones may bemore than two, for example, the heat sink 1 further includes a thirdannular zone C3 outside the second annular zone C2. When the sum of arcswhich are formed by the virtual circle falling in the third annular zoneC3 to cut the fins is X3 (ΔX3), and X1<X2<X3. When the ratios of X1, X2and X3 to the perimeter of the virtual circle are Ra1, Ra2 and Ra3,respectively, then Ra1=0.06˜0.13, Ra2=0.1˜0.18, Ra3=0.12˜0.16, and allthe values of Ra1, Ra2 and Ra3 fall in the range of 0.06˜0.2. This makesthe fins have sufficient cross-sectional area to perform thermalconduction and maintain distances between the fins to keep sufficientsizes of convection channels. Also, surface area of the fins issufficient enough under the same weight.

As shown in FIGS. 11, 38 h and 38 i, a chip mounting zone is defined onthe light board 3 (a zone on which the LED chips 311 are located). TheLED chips 311 are mounted on the chip mounting zone. At least part ofthe chip mounting zone falls in a projection of the second annular zoneC2 or the third annular zone C3. In detail, the chip mounting zoneoverlaps the heat sink 1 in outer annular zones as much as possible soas to make the corresponding fins (the first heat dissipating units 111or the second heat dissipating units 112) located on an outer edge ofthe base 13 to obtain better cooling effect and be able to correspond tomore heat dissipating units (outer heat dissipating units are greaterthan inner heat dissipating units in number). In an embodiment, at least80% of the chip mounting zone falls in the projection(s) of the secondannular zone C2 and/or the third annular zone C3. Preferably, all thechip mounting zone falls in the projection(s) of the second annular zoneC2 and/or the third annular zone C3 as shown in FIG. 38 i.

When the fins are radially arranged on the heat sink 1 with eventhickness, the number of the fins cut by the virtual circle falling inthe first annular zone C1 is N1, the number of the fins cut by thevirtual circle falling in the second annular zone C2 is N2, and N1<N2,X1<X2 would be substantially implemented. Identically, the third annularzone C3 is located outside the second annular zone C2, the number of thefins cut by the virtual circle falling in the third annular zone C3 isN3, and N1<N2<N3, X1<X2<X3 would be substantially implemented. Undersuch an arrangement, the chip mounting zone can still be arranged asshown in FIG. 38 h.

FIG. 39 is a top view of an embodiment of the heat sink 1. As shown inFIG. 39, the heat sink 1 includes multiple first heat dissipating units15 and multiple second heat dissipating units 16 (where both the firstheat dissipating units 15 and the second heat dissipating units 16 aredifferent from both the first fins 111 and the second fins 112 in FIGS.23 and 24 in naming principle and category). Both the first heatdissipating units 15 and the second heat dissipating units 16 are fins.Each first heat dissipating units 15 includes a first fin 15 a radiallyarranged on the heat sink 1 and a radial first channel 15 b. The firstchannel 15 b is a gap between two first heat dissipating units 15 a.Multiple annular zones are outward defined on the heat sink 1, namely,the first annular zone C1, the second annular zone C2 and the thirdannular zone C3. Parts of the first channel 111 b, which are located indifferent annular zones, have different widths. In the same annularzone, the first channel 15 b in an outer portion is greater than thefirst channel 15 b in an inner portion in width.

As shown in FIG. 39, the first heat dissipating units in differentannular zones may adopt different configurations of density. The firstfins of the first heat dissipating units 15 may extend in between atleast two annular zones to make the first heat dissipating unitsinterlacedly arranged and the first channel 15 b in different annularzones have different widths. Alternatively, the first fins extend inbetween at least two annular zones and are discontinuous at a junctionof the two annular zones.

As shown in FIG. 39, each second heat dissipating units 16 includes twosecond fins 16 a and a second channel 16 b formed therebetween. An endof the second channel 16 b, which is toward the central axis of the heatsink 1 is discontinuously open or closed. The first heat dissipatingunits 15 and the second heat dissipating units 16 may be located indifferent annular zones, and the annular zone in which the second heatdissipating units 16 is located is outside the annular zone in which thefirst heat dissipating units 15 is located.

As shown in FIG. 39, when an end of the second channel 16 b, which istoward the central axis of the heat sink 1 is closed, two second fins 16may extend to an outer edge of the first fin 15. Both the closed end ofthe second fins 16 and an outer edge of the first fin are located on thesame radial line but are discontinuous to form a gap as an additionalchannel.

LEDs generates heat while they are emitting. A key parameter inconsidering of thermal conduction of LEDs is thermal resistance. Thesmaller the thermal resistance is, the better the thermal conduction is.Primarily, factors of thermal resistance include length of conductionpath, conduction area and thermal conductivity of a thermo-conductivematerial. It can be expressed by the following formula:

Thermal resistance=length of conduction path L/(conduction areaS*thermal conductivity)

That is to say, the shorter the conduction path is and the larger theconduction area is, the lower the thermal conductivity is.

As shown in FIG. 29, in this embodiment, the light board 3 includes atleast one LED chip set 31 having LED chips 311.

As shown in FIG. 29, in this embodiment, the light board 3 is dividedinto three areas comprising an inner ring, a middle ring and an outerring. All the LED chip sets 31 are located in the three areas. In oneexample, the inner ring, the middle ring and the outer ring areseparately mounted by different amount of LED chip sets 31. In anotheraspect, the light board 3 includes three LED chip set 31. The three LEDchip sets 31 are respectively located in the inner ring, the middle ringand the outer ring. Each of the LED chip sets 31 separately in the innerring, the middle ring and the outer ring has at least one LED chip 311.

Four hypothetical circle lines are defined on the light board 3 as shownin FIG. 29. The outer ring is defined by the area between the outermosttwo circle lines of the four, the inner ring is defined by the areabetween the innermost two circle lines of the four, and the middle ringis located between the two areas mentioned above. In another embodiment,the light board 3 is separated into two rings(areas), and the chip sets31 are divided to be mounted on the two rings.

As shown in FIG. 29, several LED chips 311 in a circle or approximatelyin a circle compose an LED chip set. There are several LED chip sets 31on the light board 3. In a single LED chip set 31, a center distancebetween two adjacent LED chips 311 is L2. A center distance between anyLED chip 311 of any LED chip set 31 and the nearest LED chip 311 of anadjacent LED chip set 31 is L3. The ratio of L2 to L3 is 1:0.8˜2,preferably, L2:L3 is 1:1˜1.5. This makes distribution of the LED chips311 so even to accomplish an object of even light output.

FIG. 40 is a schematic view of the combination of the fins 11 and theLED chips 311 of one embodiment. As shown in FIGS. 29 and 40, in thisembodiment, when at least one fin 11 is projected onto the plane onwhich the LED chip sets 31 are located along the axial direction of theLED lamp, a projection of the fin 11 at least touches at least one LEDchip 311 of the LED chip set 31. In detail, when at least one fin 11 isprojected onto a plane on which the LED chip set 31 is located along theaxial direction of the LED lamp, a projection of the fin 11 at leasttouches at least one LED chip 311 of the LED chip set 31 in the innerring, the middle ring or the outer ring. As shown in FIG. 40, theprojection of the fin 11 touches an LED chip 311. As indicated by thearrow in the figure, it is a heat dissipating path of the LED chip 311and the fin 11. As shown in FIG. 41, the projection of the fin 41 doesnot touch the LED chip 311 in the figure. As indicated by the arrow inthe figure, it is a heat dissipating path of the LED chip 311 and thefin 11. It can be seen that the heat dissipating path of the latter islonger than the former's. As a result, by means of a projection of a finat least touching at least one LED chip 311 of the LED chip set 31 inthe inner ring, the middle ring or the outer ring, a heat dissipatingpath of the LED chip 311 can be shortened. This can reduce thermalresistance to be advantageous to thermal conduction. Preferably, a fin11 is projected onto a plane on which the LED chip set 31 is locatedalong the axial direction of the LED lamp, a projection of any fin 11(the first fin 111 or the second fin 112) at least touches at least oneLED chip 311 of the LED chip set 31.

In this embodiment, the LED chip sets 31 in outer rings corresponding tothe fins 11 are greater than the LED chip sets 31 in inner rings innumber. Here the term “corresponding to” means projection relationshipin the axial direction of the LED lamp, for example, when the LED chipsets 31 in outer rings are projected onto the fins 11 in the axialdirection of the LED lamp, the fins 11 to which the LED chips 31 inouter rings correspond are located on a relatively outer portion of theheat sink 1. Here the LED chip sets 31 in outer rings have more LEDchips 311 in number, so they need more fins 11 (area) to implement heatdissipation.

As shown in FIGS. 1 and 29, the light board 3 has an inner border 3002and an outer border 3003. Both the inner border 3002 and the outerborder 3003 separately upward extend along the axial direction of theLED lamp to form a region. An area of part of the fins 11 inside theregion is greater than an area of part of the fins 11 outside theregion. As a result, the most of the fins 11 can correspond to the lightboard 3 (a shorter heat dissipating path) to enhance heat dissipatingefficiency of the fins 11 and increase effective area of heat conductionof the fins 11 to the LED chips 311.

As shown in FIGS. 3, 5 and 29, a reflecting region 3001 is disposed in aregion between the inner ring and an outer edge of the light board 3 toreflect the upward light to the light output surface 43. This can reduceloss of light in an opposite direction of light output in the axialdirection of the LED lamp to increase overall intensity of light output.

As shown in FIGS. 4 and 29, the light board 3 is formed with a thirdaperture 32 separately communicating with the first heat dissipatingchannel 7 a and the second heat dissipating channel 7 b. For example,the third aperture 32 communicates with spaces between the fins 11 andthe chamber of the lamp shell 2 to form air convection paths between thespaces between the fins 11 and between the chamber of the lamp shell 2and the outside of the Led lamp. The third aperture 32 is located insidethe inner ring of the LED lamp. Thus, it would not occupy the space ofthe reflecting region 3001 to affect reflective efficiency. In detail,the third aperture 32 is located at a central region of the light board3 and both the first air inlet 2201 and the second air inlet 1301 makeair intake through the same aperture (the third aperture 32). In oneexample, after convection air passes through the third aperture 32, andthen enters the first air inlet 2201 and the second air inlet 1301. Thethird aperture 32 is located at a central region of the light board 3,so both the first air inlet 2201 and the second air inlet 1301 cancommonly use the same air intake. Thus, this can prevent occupying anexcessive region of the light board 3 and prevent the usable regionalarea of the light board 3 for disposing the LED chips 311 fromdecreasing due to multiple air intakes. On the other hand, the sleeve 21corresponds to the third aperture 32, so convection air may have aneffect of thermal isolation to prevent temperatures inside and outsidethe sleeve 21 from mutually affecting each other when air enters. Inother embodiments, if both the first air inlet 2201 and the second airinlet 1301 are located at different positions, then the third aperture32 may be multiple in number to correspond to both the first air inlet2201 and the second air inlet 1301. In detail, as shown in FIG. 42, thethird aperture 32 may be located at a middle portion or outer portion orbetween the LED chips 311 to correspond to both the first air inlet 2201and the second air inlet 1301 stopped

As shown in FIG. 29, in an embodiment, in the inner ring, both adjacenttwo of the LED chips 311 and the axis of the LED lamp form a centerangle A; in the middle ring, both adjacent two of the LED chips 311 andthe axis of the LED lamp form a center angle B. The center angle B isless than the center angle A in degree. In the outer ring, both adjacenttwo of the LED chips 311 and the axis of the LED lamp form a centerangle C, and the center angle C is less than the center angle B indegree. For example, the LED chips 311 in the outer ring are more thanthose in the middle ring in number. Thus, a distance between adjacenttwo of the LED chips 311 in the outer ring is not much greater than adistance between adjacent two of the LED chips 311 in the middle ring,even, the two distances may be similar or identical. As a result, bothdistribution of the LED chips 311 and light output will be very even. Inone example, the LED chip sets 31 are multiple in number and areannularly mounted on the light board 3. A center angle formed byadjacent two of the LED chips 311 in an inner portion and the axis ofthe LED lamp is greater than a center angle formed by adjacent two ofthe LED chips 311 in an outer portion and the axis of the LED lamp. Thatis, The LED chips 311 of outer LED chip sets 31 are greater than the LEDchips 311 of inner LED chip sets 31 in number such that a distancebetween adjacent two of the LED chips 311 of outer LED chip sets 31 isless than a distance between adjacent two of the LED chips 311 of innerLED chip sets 31. As a result, both distribution of the LED chips 311and light output will be very even.

As shown in FIG. 40, in one embodiment of the present invention, thelight board 3 is provided with an insulative layer 34 with highreflectivity. The insulative layer 34 may adopt thermal grease. Theinsulative layer 34 is smeared on the light board 3 to an edge thereof.A distance between the LED chips 311 at the outermost position and anedge of the light board 3 is greater than 4 mm. Preferably, a distancebetween the LED chips 311 at the outermost position and an edge of thelight board 3 is greater than 6.5 mm but less than 35 mm. In addition, acreepage distance between the outermost LED chips 311 and the heat sink1 can be guaranteed to prevent arc occurring between the LED chips 311and the heat sink. In addition, the insulative layer 34 may also have aneffect of thermal isolation to prevent overheating and deformation ofthe lamp cover 4.

FIG. 43 is a schematic view of the light board 3 in this embodiment. Asshown in FIG. 43, in this embodiment, the LED chip sets 31 are at leasttwo in number. The at least two LED chip sets 31 are annularly arrangedon the light board 3 in order. Each LED chip set 31 includes at leastone LED chip 311. Each LED chip 311 of one of the LED chip sets 31 onthe light board 3 is radially interlacedly arranged with any one LEDchip 311 of adjacent one of the LED chip sets 31 on the light board 3.That is, the LED chips 311 of different LED chip sets 31 are located indifferent directions in a radial direction of the LED lamp. In oneexample, if any line starting with the axis of the LED lamp andextending toward a radial direction of the LED lamp cuts two or more ofthe LED chips 311, then it will cut different positions of these two ormore LED chips 311 and will not cut the same positions of these two ormore LED chips 311. As a result, if there is convection on the lightboard 3 and air radially flows on the light board 3, the contact betweenair and the LED chips 311 will be more sufficient and a better effect ofheat dissipation will be obtained because of the airflow paths. Inaddition, in the aspect of lighting effect, such distribution of the LEDchips 311 is more advantageous to uniformity of light output.

In this embodiment, an open region 312 is formed between adjacent two ofthe same LED chip set 31 to allow air to flow between the LED chips 311to bring out heat generated from the working LED chips 311. The openregion 312 between any two adjacent LED chips 311 of one of adjacent twoof the chip sets 31 on the light board 3 interlaces to and communicateswith the open region 312 between any two adjacent LED chips 311 ofanother one of the chip sets 31 on the light board 3 in a radialdirection of the LED board 3. As a result, if there is convection on thelight board 3 and air radially flows on the light board 3, the contactbetween air and the LED chips 311 will be more sufficient and a bettereffect of heat dissipation will be obtained because of the airflowpaths. If both the open region 312 between any two adjacent LED chips311 of one of adjacent two of the chip sets 31 on the light board 3 andthe open region 312 between any two adjacent LED chips 311 of anotherone of the chip sets 31 on the light board 3 of the LED board 3 are inthe same radial direction, then air will flow along radial directions ofthe light board 3. The contact between air and the LED chips 311 willdecrease to be disadvantageous to heat dissipation of the LED chips 311because of the airflow paths.

For example, three LED chip sets 31 are annularly disposed along aradial direction of the light board 3 in order, any open regions 312 ofthe three LED chips 31 are not in the same direction in a radialdirection. Thus, convection paths on the light board 3 can be optimizedto increase efficiency of the heat dissipation.

In some applications, when LEDs are emitting, a light distributionregion will be formed under the LED lamp. This means distribution ofintensity of light source. The design of the LED lamp aims forconcentrating the light distribution region to a specific zone toincrease local intensity.

FIGS. 44a ˜44 f are schematic views of some embodiments of the lightboard 3. As shown in FIGS. 44a and 44b , the light board 3 includes afirst region 35 for installing the LED chip set 31, a second region 36inside the first region 35 and a third region 37 outside the firstregion 35. The first region 35 restricts a range of installing the LEDship set 31. The first, second and third regions 35, 36, 37 may beprovided with insulative layers (not shown) with reflectivity on thesurface.

As shown in FIGS. 44a and 44b , the third region 37 is located away fromthe first region 35 in a radial direction of the LED board 3. Thedistance between the third region 37 and the first region 35 isgradually increase in the axial direction. Thus, a surface of the thirdregion 37 is formed with an outer reflecting region 371 outside the LEDchip set 31 so as to guide at least part of light from the LED chip set31 to the light output surface. This can concentrate light to a specificarea.

As shown in FIG. 44 b, the second region 36 is located close to thecenter in a radial direction of the LED board 3. The distance betweenthe second region 36 and the first region 35 is gradually increase inthe axial direction. Thus, a surface of the second region 36 is formedwith an inner reflecting region 361 inside the LED chip set 31 so as toguide at least part of light from the LED chip set 31 to the lightoutput surface 43. This can concentrate light to a specific area.

In the above embodiments, both the inner reflecting region 361 and theouter reflecting region 371 of the light board 3 and both the innerreflecting surface 4301 and the outer reflecting surface 4302 of thelamp cover 4 may be arbitrarily combined and arranged to implementvarious optical effects. For example, only both the inner reflectingregion 361 and the inner reflecting surface 4301 are disposed, only boththe outer reflecting surface 4302 and the outer reflecting region 371are disposed, or both either of the inner reflecting region 361 and theinner reflecting surface 4301 and either of the outer reflecting surface4302 and the outer reflecting region 371 are disposed.

As shown in FIGS. 44a and 44 b, the inner reflecting region 361 or theouter reflecting region 371 is a flat plane and inclines to the firstregion 35 to form an angle or is a curved surface.

In some embodiments, a direction of light output of the LED chips 311can be adjusted by changing a mounting direction thereof. In detail,adjusting a structure of the light board 3 can make the LED chips 311have various effects of light output. For example, as shown in FIG. 44c, in some embodiments, the light board 3 includes a first region 35 forinstalling the LED chip set 31, a second region 36 inside the firstregion 35 and a third region 37 outside the first region 35. There areseveral LED chip sets 31 on the light board 3. The LED chip sets 31 areannularly arranged on the light board 3. In this embodiment, at leastone LED chip set 31 is located in the third region 37 which inclines tothe first region 36 to form an angle. At least one LED chip set 31located in the third region 37 can change an angle of light output topresent a different effect of light output. This can change distributionof intensity.

Identically, at least one LED chip set 31 is located in the secondregion 36 which inclines to the first region 36 to form an angle. Atleast one LED chip set 31 located in the second region 36 can change anangle of light output to present a different effect of light output.This can change distribution of intensity.

The light board 3 shown in FIG. 44c as an example, the LED chip sets 31are three in number and the outermost LED chip set 31 is located in thethird region 37. The LED chip set 31 in a middle position among thethree LED ship sets 31 is located in the first region 35, and the LEDchip set in an innermost position is located in the second region 36.

In the above embodiment, both the second and third regions 36, 37 areused for installing the LED chips 311. Each LED chip 311 corresponds toone second region 36 or third region 37. Both the second and thirdregions 36, 37 may also be an integrated region on which the LED chips311 of the same LED chip set 31 are mounted.

As shown in FIG. 44 d, in some embodiments, to enhance lightingefficiency of the LED chips 311, surfaces of the LED chips 311 areseparately disposed with silicone layers 313. Each LED chip 311 isdisposed with an individually silicone layer 313. An out surface of thesilicone layer 313 is a convex surface to form a lens which is capableof focusing light from the LED chips 311. This makes an effect of lightoutput better and is advantageous to increase of illuminance. Inaddition, the silicone layer 313 can also improve efficiency of thermalradiation (increase its radiating area) to be advantageous to heatdissipation of the LED chips 311.

As shown in FIG. 44 e, in some embodiments, the light source includesthe light board 3, the LED chips 311 and the silicone layers 313. Thesilicone layer 313 includes a first silicone layer 3131 on a surface ofthe light board 3 and a second silicone layer 3132 on a surface of theLED chip 311. The first silicone layer 3131 cloaks and isolates thelight board 3 to make the light board insulated. The second siliconelayer 3132 has a convex surface to form a lens which focuses light fromthe LED chips 311. This makes an effect of light output better and isadvantageous to increase of illuminance. Also, considering themanufacturing process of the first silicone layer 3131 and the secondsilicone layer 3132, the thickness of the first silicone layer 3131 isapproximately the same as that of the LED chip 311, such that the firstsilicone layer 3131 will not cause any effect in the emitting of the LEDchip 311.

Both the first silicone layer 3131 and the second silicone layer 3132are integratedly formed to be the silicone layer 313 for resisting dust.At this time, the lamp cover 4 may be omitted to increase lightingefficiency (unavoidably, the lamp cover 4 obstructs part of light tocause light loss). As shown in FIG. 44 f, in some embodiments, siliconein LED chip packing may be omitted. The silicone layer 313 is directlydisposed outside the fluorescent powder 314. That is, the fluorescentpowder 314 is disposed outside the chip 3111 and the silicone layer 313is disposed outside the fluorescent powder 314. In addition, thesilicone layer 313 can also improve efficiency of thermal radiation(increase its radiating area) to be advantageous to heat dissipation ofthe LED chips 311.

FIGS. 45a ˜45 g are top views of some embodiments of the light board 3mwhich show different distribution of the LED chips 311. In FIG. 45 a,the LED chips 311 of a single LED chip set 31 are directly mounted onthe bae board 33 at regular intervals. That is, a distance between anyadjacent two of the LED chips 311 is identical to make the whole lightboard 3 capable of even lighting. In FIGS. 45 b, and 45 c, the LED chips311 of a single LED chip set 31 are arranged in array. The array may bea matrix as shown in FIG. 45b or a triangular array as shown in FIG. 45c. Of course, the LED chips 31 may be arranged in a concentric annularshape as above-mentioned. Such an array can concentrate the LED chips311 to a local area on the base board 33 to generate a concentratedlighting effect with even light output in the local area.

FIG. 45d shows an embodiment of multiple LED chip sets 31 independentlyforming respective arrays, in which each LED chip set 31 contains LEDchips 311. A triangular dotted box encompasses an LED chip set 31. Adistance is kept between two adjacent arrays, which is greater than adistance between adjacent two of the LED chips 311. Thus, an airflowchannel is formed between two adjacent arrays to promote air convectionon the light board 3.

As shown in FIG. 45 e, in some embodiments, each LED chip 311 of the LEDchip set 31 is of a rectangular shape with a long side and a short side.As shown in FIG. 45 e, the LED chips 311 are arranged along a circle andthe long sides are arranged along radial directions of the LED lightboard 3 to make the LED chips 311 present a radial arrangement. Thus,more LED chips 311 can be arranged on this circle and concentrated in asmall area. Meanwhile, the long sides provide longer convection paths inradial directions to increase thermal exchange between airflow and theLED chips 311. In addition, the LED chips 311 are arranged along acircle and the short sides are arranged along radial directions of theLED light board 3 to make the LED chips 311 distributed on a large areaand to shorten a distance between two adjacent LED chips 311. Such anarrangement makes the LED chips 311 look like a lighting ring. Theabovementioned two arrangements may be jointly or alternativelyimplemented.

FIGS. 45f ˜45 g are local schematic views of some diverse embodiments ofthe light board 3. As shown in FIGS. 45f and 45 g, in some embodiments,the base board 33 of the light board 3 is provided with one or morereflecting cups 334. Opening s of the reflecting cups 334 are toward anopposite direction of the base board 33. The inside bottom of eachreflecting cup 334 is disposed with an LED chip 311. An inner side ofthe reflecting cup 334 is formed with a material with high reflectivity.Available solutions are to coat or electroplate the inner side of thereflecting cup 334 with a coating with high reflectivity or directlymake the reflecting cup 334 with a material with high reflectivity andpolish the inner side. The inner side of the reflecting cup 334 canreflect lateral light output of the LED chip 311 to make the light fromthe LED chip 311 focused a direction to which the LED chip 311 isdirected. FIG. 45g is a variation of FIG. 45 f. There are multiple LEDchips 311 mounted on the inside bottom of each reflecting cup 334. Inone example, each reflecting cup 334 is disposed with at least one LEDchip 311.

FIGS. 46a ˜46 c are perspective views of the power source 5 of oneembodiment at different viewpoints. FIG. 46d is a main view of the powersource 5 of one embodiment. The power source 5 is electrically connectedto the LED chips 311 to power the LED chips 311. As shown in FIGS. 46a˜46 c, the power source 5 includes a power board 51 and a plurality ofelectronic components mounted thereon.

As shown in FIG. 46 c, a transformer 54 in the electronic componentsincludes a core 541 and coils 542. The core 541 has a room in which thecoils 542 is received. The room has an opening in the axial direction ofthe LED lamp so as to make heat generated from the coils 542 and thecore 541 move upward. Also, the heat dissipating direction of thetransformer 54 is consistent with the convection path of the first heatdissipating channel 7 a (as mentioned in the description of FIG. 4) forbeing advantageous to heat dissipation.

As shown in FIGS. 46b and 46c , the room is provided with two openingsat two ends in the axial direction of the LED lamp to increase heatdissipating effect to the coils 542. In addition, after the coils 542are installed in the room of the core 541, a gap is kept between thecoils 542 and the room to allow air to flow. This can further increaseheat dissipating effect to the coils 542.

As shown in FIG. 46b , the transformer 54 has a first side 5401 and asecond side 5402, both of which are perpendicular to the power board.The first side 5401 is perpendicular to the axial direction of the lamp.The first side 5401 is less than the second side 5402 in area. Thus,such an arrangement of the small side can reduce resistance toconvection of the first heat dissipating channel 7 a.

As shown in FIG. 46 c, the electronic components include at least oneinductor 755 including an annular core 551. A coil is wound around theannular core 551 (not shown). An axis of the annular core 551 isparallel to the axis of the LED lamp to make the coil have larger areato be in contact with convection air. This can further increase heatdissipating effect to the inductor 55. In addition, a shape of theannular core 551 corresponds to the convection path of the first heatdissipating channel 7 a. Thus, convection air can pass through theinside of the annular core 551 to further increase heat dissipatingeffect to the inductor 55.

As shown in FIGS. 46a and 46 b, heat-generating elements in theelectronic components include integrated circuits (ICs) 56, diodes,transistors, the transformer 54, the inductor 55 and resistors. Theseheat-generating elements are separately mounted on the power board 51 todistribute heat-generating sources and prevent local high temperature.In addition, the heat-generating elements may be mounted on differentsurfaces of the power board 51 to perform heat dissipation. At thistime, the heat-generating elements are in contact with correspondingheat dissipating elements.

As shown in FIGS. 46a and 46 b, at least one IC 56 is arranged to bemounted on different surface as other heat-generating elements arearranged of the power board 51. As a result, the heat-generating sourcescan be separated to avoid local high temperature and influence to the IC56 from the other heat-generating elements.

As shown in FIGS. 46a and 46b , in a direction perpendicular to thepower board 51 (i.e. projection relationship in a directionperpendicular to the power board 51), the IC 56 does not overlap anyheat-generating elements to avoid heat accumulation.

As shown in FIG. 22, the power board 51 is parallel to the axis of theLED lamp. Thus, in the axial direction of the LED lamp, the power board51 is divided into an upper portion and a lower portion. Arrangingspaces of both the upper portion and the lower portion are identical orapproximately identical to form better layout of the electroniccomponents. Besides, if the power board 51 inclines toward the axis ofthe LED lamp, then air flow may be obstructed and it is disadvantageousto heat dissipation of the power source 5.

As shown in FIGS. 1 and 22, the power board 51 divides the lamp shell 2into a first portion 201 and a second portion 202. Area of the ventinghole 222 corresponding to the first portion 201 is greater than area ofthe venting hole 222 corresponding to the second portion 202. Thus, whenimplementing layout of electronic components, most or all of electroniccomponents or some thereof which generate a large amount of heat such asinductors, resistors, transformers, rectifiers or transistors may bedisposed in the first portion 201.

As shown in FIG. 22, the power board 51 divides an inner chamber of thelamp shell 2 into a first portion 201 and a second portion 202. Thefirst portion 201 is greater than the second portion 202 in volume. Whenimplementing layout of electronic components, most or all of electroniccomponents or some thereof which generate a large amount of heat such asinductors, resistors, transformers, rectifiers or transistors may bedisposed in the first portion 201.

Please simultaneously refer to FIGS. 22 and 29, further, area of firstair inlet 2201 corresponding to the first portion 201 is greater thanarea of the second air inlet 2202 corresponding to the second portion202. Thus, more air can flow into the first portion 201 to perform heatdissipation to the electronic components. Here, the specific descriptionof the air inlet is that the first air inlet 2201 is divided into twoportions by the power board 51, one of the two portions corresponds tothe first portion 201 and the other one of the two portions correspondsto the second portion 202 so as to make more air flow into the first airinlet 2201 and enter the first portion 201.

As shown in FIG. 22, the electronic components 501 includeheat-generating elements 501. At least one of the heat-generatingelements 501 is adjacent to the lamp head 23 through which heat isdissipated without occupying resource of heat dissipation of the firstheat dissipating channel 7 a. The at least one heat-generating element501 abovementioned is an inductor, a resistor, a rectifier or a controlcircuit.

As shown in FIG. 22, heat of the at least one heat-generating element istransferred to the lamp head 23 through thermal conduction or radiationand dissipated to air through the lamp head 23.

As shown in FIG. 22, the at least one heat-generating element 501 is inthermal contact with the lamp head 23. In detail, the at least oneheat-generating element 501 is located in the lamp head 23. Theheat-generating element 501 is in contact with the lamp head 23 througha thermal conductor 53 and the heat-generating element 501 is fastenedto the lamp head 23 through the thermal conductor 53. Therefore, thethermal conductor not only performs an effect of heat transfer but alsofixes the heat-generating element 501 to avoid loosening of theheat-generating element 501. The phrase “the heat-generating element 501is located in the lamp head 23” means both the lamp head 23 and theheat-generating element 501 have an overlapping area in a projectionperpendicular to the axis of the LED lamp.

As shown in FIG. 22, the thermal conductor 53 is disposed in the lamphead 23 through filling to implement connection between the lamp head 23and the heat-generating element 501. The thermal conductor 53 onlycloaks an end portion of the power source 5 and is higher than theventing 222 in position to prevent overweight resulting from the thermalconductor 53. Additionally, the thermal conductor 53 adopts aninsulative material to guarantee safety and prevent the electroniccomponents and metal portion 231 of the lamp head 23 from being incontact. In other embodiments, the thermal conductor 53 may also be awire connecting the power source 5 to the lamp head 23 (not shown).

As shown in FIG. 22, the lamp head 23 includes the metal portion 231,which is in thermal contact with the thermal conductor 53. That is, atleast part of an inner side of the metal portion 231 constitutes a wallof the inner chamber of the lamp shell 2 to make the thermal conductordirectly connect with the metal portion 231 and perform heat dissipationby the metal portion 231. Part of the metal portion 231 would performheat dissipation through air, and another part of the metal portionwould perform heat dissipation through a lamp socket connecting to themetal portion 231.

As shown in FIGS. 2 and 46 a, in this embodiment, at least one of theelectronic components of the power source 5, which is the most adjacentto the first air inlet 2201 of the first heat dissipating channel 7 a isa heat intolerance component, such as a capacitor, especially for anelectrolytic capacitor. This arrangement can avoid overheating of theheat intolerance component to affect its performance.

In addition, to reduce influence of an electrolytic capacitor 502suffering heat from the heat-generating elements, a surface of theelectrolytic capacitor can be provided with an anti-radiation layer or athermo-isolation layer (not shown). The thermos-isolation layer mayadopt existing plastic material, and the anti-radiation layer may adoptexisting paint, silver plate layer, aluminum foil or otheranti-radiation materials.

As shown in FIG. 46 a, in this embodiment, at least part of at least oneof the electrolytic capacitors 502 is not located within the power board51, i.e. at least part of the electrolytic capacitor exceeds the powerboard 51 in the axial direction of the LED lamp. Under a condition ofthe same number of the electronic components, length and material costof the power board 51. In addition, this can make the electrolyticcapacitor further adjacent to the first air inlet 2201 to ensure theelectrolytic capacitor to be located in a relatively low temperaturearea.

As shown in FIG. 22, a position of at least one of the heat-generatingelements 501 in the axial direction of the LED lamp is higher than aposition of the venting hole 222. Most heat of the heat-generatingelement 501 higher than the venting hole 222 is dissipated through thelamp head 23 or other paths. Thus, most heat therefrom is not dissipatedthrough the venting hole 222, and convection speed of the first heatdissipating channel 7 a would not be affected. The heat-generatingelement is an IC, a transistor, a transformer, an inductor, a rectifieror a resistor.

As shown in FIG. 22, the power board 51 is divided into an upper partand a lower part in the axial direction of the LED lamp. Heat-generatingelements are arranged in both the upper part and the lower part. Atleast one of the heat-generating elements in the upper part is locatedabove the venting hole 222 to lower the temperature of the upper partnear the venting hole 222. This can increase an air temperaturedifference between two venting holes 222 in the upper part and the lowerpart to enhance convection.

As shown in FIGS. 2, 3 and 46 a, when the power board 51 is assembled inthe lamp shell 2, it has a first portion in the lamp neck 22 and asecond portion in the sleeve 21. The second portion more adjacent to thefirst air inlet 2201 of the first heat dissipating channel 7 a than thefirst portion. Because of such an arrangement, convention air will reachthe second portion first. That is, the second portion is better than thefirst portion in an effect of heat dissipation. Thus, at least part ofheat intolerance elements (e.g. electrolytic capacitors or otherelements which is sensitive to high temperature) should be disposed inthe second portion. Preferably, all electrolytic capacitors are disposedin the second portion. The power board 51 of the second portion isgreater than the first portion in area, so the power board 51 of thesecond portion has more space for accommodating electronic components tobe advantageous to more heat intolerance elements being disposed in thesecond portion. In this embodiment, heat intoleranceelements/thermo-sensitive elements may be separately mounted on twoopposite sides of the second portion. In other embodiments, hotterelectronic components may be disposed in the second portion (e.g.transformers, inductors, resistors, ICs or transistors) for better heatdissipation.

FIG. 51 is a schematic of an embodiment of the power source 5. As shownin FIG. 51, the power board 51 has a thermo-isolation plate 513. Thepower board 51 is divided into two zones by the thermos-isolation plate513. One of the two zones is used to be mounted by heat-generatingelements (e.g. transformers, inductors, resistors, etc.), and the otherzone is used to be mounted by heat intolerance/thermos-sensitiveelements (e.g. electrolytic capacitors). That is, the thermos-isolationplate 513 partitions heat-generating elements and heatintolerance/thermo-sensitive elements to prevent the latter from beingaffected by thermal radiation from the former. In other embodiments,heat-generating elements are disposed in both zones. That is, thethermo-isolation plate 513 partitions two heat-generating elements toprevent mutual thermal radiation which causes thermal accumulation. Inanother aspect, temperature is an important factor of thermal radiation,so avoiding mutual thermal radiation between heat-generating elementscan rise a temperature difference between a heat-generating element andair therearound so as to improve efficiency of thermal radiation.Preferably, the thermo-isolation plate 513 is arranged along the axis ofthe LED lamp or the convection direction of the first heat dissipatingchannel 7 a to make heat in two sides would not make convection in awidth direction of the power board 51 to prevent heat gathering whenconvection is processing. The thermo-isolation plate is extendedlyarranged along the convection direction of the first heat dissipatingchannel 7 a. That is, the thermo-isolation plate 513 is extendedlyarranged along the axis of the LED lamp, so obstruction to convectionair would not occur. In other embodiments, the thermo-isolation plate513 may be slant to form a guiding effect to air.

Furthermore, the thermo-isolation plate 513 may be a circuit board, sothe thermo-isolation plate 513 may be disposed with electroniccomponents to increase area for mounting electronic components.

The function of the thermo-isolation plate 513 may be replaced withelectronic components. As shown in FIG. 46d , there are three electroniccomponents 503, 504, 505 on the power board 51. At least parts ofprojections of the three electronic components 503, 504, 505 in a radialdirection of the LED lamp (or a width direction of the power board 51)overlap with another one. The one 504 of the three electronic components503, 504, 505 is located between the other two 503, 505 to avoid mutualthermal radiation between the two electronic components 503, 505. Thisis advantageous to forming a greater temperature difference between theheat-generating elements and air therearound and radiating heat from theheat-generating elements to air. The abovementioned two electroniccomponents 503, 505 are respective a heat-generating element (such as atransformer, a resistor or a transistor) and a heat intoleranceelements/thermo-sensitive element (such as an electrolytic capacitor),so at least part of heat from the heat-generating elements (one of theelectronic components 503 and 505) would be thermally radiated to thein-between electronic component 504 to reduce thermally radiativeinfluence to the heat intolerance elements/thermo-sensitive element fromthe heat-generating elements.

In the other embodiment of the present invention, the three electroniccomponents 503, 504, 505 on the power board 51 positioned as mentionedabove, both electronic components 503, 505 are a heat-generating element(such as a transformer, a resistor or a transistor), so at least part ofheat generated from the heat-generating elements (electronic components503 and 505) would be thermally radiated to the in-between electroniccomponent 504. Under these circumstances the electronic component 504plays a role for preventing the heat generated from the twoheat-generating elements being superposed to effect the working qualityof the LED lamp due to overheated temperature occurred in the powerboard 51 area.

Preferably, the in-between electronic component 504 adopts non-heatingor heat-resistant electronic component such as a temperature sensor or acapacitor.

As shown in FIG. 46 d, in other embodiments, there are three electroniccomponents 506, 507, 508 on the power board 51. At least parts ofprojections of the three electronic components 506, 507, 508 in theaxial direction of the LED lamp (or in a width direction of the powerboard 51, i.e. along a convection direction of the first heatdissipating channel 7 a) overlap with another one. The one 507 of thethree electronic components 506, 507, 508 is located between the othertwo 506, 508 to avoid mutual thermal radiation between the twoelectronic components 506, 508. This is advantageous to forming agreater temperature difference between the heat-generating elements andair therearound and radiating heat from the heat-generating elements toair. The abovementioned two electronic components 506, 508 areheat-generating elements (such as transformers, resistors, inductors ortransistors), so at least part of heat from the heat-generating elements506, 508 would be thermally radiated to the in-between electroniccomponent 507 to reduce thermally radiative influence to the heatintolerance elements/thermo-sensitive element from the heat-generatingelements and to avoid heat accumulation. In this embodiment, by such anarrangement of the electronic component 507, it will obstruct upwardconvection air flow. For example, after heat from the lower electroniccomponent 506 is brought out by convection air, the convection air mustbypass the in-between electronic component 507 to avoid direct contactwith the upper electronic component 508. In this embodiment, thein-between electronic components 507 is a non-heat-generating element(such as a capacitor). In other embodiments, the other two electroniccomponents 506, 508 are a heat-generating element (such as transformers,resistors or inductors) and a heat intolerance element (such as acapacitor).

FIG. 52 is a schematic view of an embodiment of the power source 5. Insome embodiments, to improve radiative efficiency of the heat-generatingelements of the power source 5, a radiating layer 509 may be provided onsurfaces of the heat-generating elements. Heat from workingheat-generating elements can be thermally conducted to the radiatinglayer 509, and then the radiating layer 509 radiates the heat tosurrounding air to bring out hot air when convection is processing inthe first heat dissipating channel 7 a. The radiating layer 509 isgreater than the heat-generating elements in radiative efficiency so asto significantly improve efficiency of heat dissipation of theheat-generating elements with the radiating layer 509. In thisembodiment, the radiating layer 509 may adopt existing black glue toincrease an effect of radiating to air. The black glue covers a surfaceof the power source 5 and may be in thermal contact with the lamp head23. That is, part of heat from the heat-generating elements of the powersource 5 is radiated to surrounding air and another part thereof isthermally conducted to the lamp head 23 through the black glue (notshown). The lamp head 23 is metal, so the heat can be further dissipatedto the outside through the lamp head 23. In this embodiment, the blackglue is of a thin layer attached on a surface of a heat-generatingelement without obstructing convection in the first heat dissipatingchannel 7 a. The black glue with light weight would not add substantialweight. In other embodiments, the black glue may be selectivelydisposed, for example, the black glue is disposed on heat-generatingelements with high heat such as transformers, inductors or transistors.

In addition, in the above embodiment, to further increase radiativeefficiency of the radiating layer 509, the radiating layer 509 can beconfigured to be a rough surface to increase surface area.

FIG. 47 is a schematic view of an embodiment of the power source 5,which can be applied to the power source 5 of the LED lamp shown in FIG.4. As shown in FIG. 47, in some embodiments, the power board 51 isdivided into a first mounting zone 511 and a second mounting zone 512 byan axis X. The axis X is between the first mounting zone 511 and thesecond mounting zone 512 as a border. Total weight of the electroniccomponents on the second mounting zone 512 is greater than total weightof the electronic components on the first mounting zone 51. The firstmounting zone 511 is provided with a counterweight 52 to balance the twozones 511, 512 of the power board 51 in weight. This can preventunbalanced weight of the two zones 511, 512 of the power board 51 andprevent the hung LED lamp from tilting because of unbalanced weight.

FIG. 48 is a main view of the counterweight 52 of FIG. 47. FIG. 49 is aside view of FIG. 48. As shown in FIGS. 48 and 49, in some embodiments,the counterweight 52 is a heat dissipating element with heat dissipatingfunction and is disposed on the power board 51. In some embodiments, theheat dissipating assembly has fins 521 for increasing heat dissipatingarea. The counterweight 52 is made of metal with highthermo-conductivity such as aluminum or copper. In this embodiment, thefins 521 are extendedly arranged along the axial direction of the LEDlamp. A channel is formed between two adjacent fins 521 as an airpassage. Such an arrangement can increase heat dissipating area of thecounterweight 52. In one embodiment, the counterweight 52 includes along side and a short side. The channels are parallel with the long sideand the long side is configured to be parallel with the axis of the LEDlamp or substantially parallel with the direction of airflow to make theair flow smoothly.

As shown in FIG. 47, the electronic components include heat-generatingelements which generate heat when working. At least one heat-generatingelement is adjacent to a heat dissipating assembly to dissipate part ofheat through the heat dissipating assembly. Preferably, transformers,inductors, resistors, diodes, transistors or ICs of the heat-generatingelements are adjacent to the heat dissipating assembly. More preferably,transformers, inductors, resistors, diodes, transistors or ICs of theheat-generating elements are in direct contact with the heat dissipatingassembly.

In one embodiment of the present invention, two opposite sides of thecircuit board all comprise the counterweight 52, such that the heatdissipating efficiency of the circuit board 51 and the weight balancebetween two sides of the circuit board 51 can be improvedsimultaneously.

As shown in FIG. 47, in some embodiments, the power board 51 is dividedinto a first mounting zone 511 and a second mounting zone 512 by an axisX. The axis X is between the first mounting zone 511 and the secondmounting zone 512 as a border. The second mounting zone 512 is greaterthan the first mounting zone 511 in number of electronic components tomake airflow of the first mounting zone 511 smooth and to reduceobstruction of the electronic components. In this embodiment, both thefirst mounting zone 511 and the second mounting zone 512 haveheat-generating elements to distribute heat sources.

As shown in FIGS. 4, 47 and 50, in some embodiments, the first heatdissipating channel 7 a includes an inner channel 7 a 1 and an outerchannel 7 a 2. The outer channel 7 a 2 is formed between the electroniccomponents on an edge of the power board 51 and an inner wall of theinner chamber of the lamp shell 2. The inner channel 7 a 1 is formed ingaps between the electronic components. This arrangement can enhance aneffect of heat dissipation of the power source 5. In detail, the powerboard 51 in FIG. 47 is divided into two portions (a left portion and aright portion, not necessarily symmetrical), namely, a first portion anda second portion. Both the first portion and the second portion haveelectronic components. The outer channel 7 a 2 is formed between theelectronic components on both the first portion and the second portionand the inner wall of the lamp shell 2. The inner channel 7 a 1 isformed between the electronic components separately on the first portionand the second portion. In this embodiment, a transformer 54 of theelectronic components includes a core 541 and coils 542. The core 541has a chamber in which the coils 542 are disposed. An opening is formedat a side of the chamber in a radial direction to expose the coils 542.The opening corresponds to the inner channel 7 a 1 or the outer channel7 a 2 to make heat from the coils 542 is rapidly ejected throughconvection in the inner channel 7 a 1 or the outer channel 7 a 2.Preferably, two openings are separately formed at two sides of thechamber in a radial direction. One of the two openings corresponds tothe inner channel 7 a 1 and the other one thereof corresponds to theouter channel 7 a 2 to further enhance heat dissipation of thetransformer.

FIGS. 53a ˜53 c are schematic view of various embodiments of the powersource board 51. As shown in FIG. 53 a, the power board 51 includesmultiple sub-boards 512 which electrically connect to each other. Asshown in FIG. 53 a, the sub-boards 512 are connected by one or morewires 513. When multiple wires are used, they can be combined to be aflexible flat cable. Relative positions of the sub-boards 512 can bechanged by bending the wire 513, for example, two sub-boards 512 arekept parallel at an interval and are separately mounted by differentgroups of electronic components. As shown in FIG. 53 b, the sub-boards512 are connected by one or more electric connectors 514 by which thesub-boards 512 can be firmly combined in a parallel or coplanar manner.For example, two sub-boards 512 are kept parallel at an interval and areseparately mounted by different groups of electronic components. Asshown in FIG. 53 c, the power board 51 includes a first zone 51 a and asecond zone 51 b. The second zone is greater than the first zone inwidth for accommodating more heat intolerance electronic components. Thesecond zone 51 b is adjacent to an intake 172 of the base 17 and thefirst zone 51 a is adjacent to the venting hole 222 of the lamp neck 22.

FIG. 54 is a cross-sectional view of the LED lamp of one embodiment. Asshown in FIG. 54, the power board 51 divides the heat dissipatingchannel (here it means the first heat dissipating channel 7 a) into afirst channel S1 and a second channel S2 along the axis of the heatdissipating channel. The power board 51 includes a first side and asecond side. The first side corresponds to the first channel S1 and thesecond side corresponds to the second channel S2.

When an electronic component has large volume, the heat dissipatingchannel it is located has to need correspondingly large volume. As aresult, a sufficient channel space can be kept after the volume of theheat dissipating channel minus the total volume of the electroniccomponent. Thus, when the first channel S1 is less than the secondchannel S2 in volume, volume of the electronic components on the firstside (a total volume of all electronic components on the first side)must be less than volume of the electronic components on the second side(a total volume of all electronic components on the second side). Theratio of volume of the first heat dissipating channel S1 to the secondchannel S2 is defined as R1, and R1 is between 0.3 and 0.5. The ratio ofvolume of the electronic components on the first side to volume of theelectronic components on the second side is defined as R2, and R2 isbetween 0.05 and 0.2. In the aspect of the ratio relationship, the ratioR1 of volume of the first channel S1 to volume of the second channelmust be less than the ratio R2 of volume of the electronic components onthe first side to volume of the electronic components on the secondside. If weight of the electronic components on the first side is lessthan weight of the electronic components on the second side, then acounterweight (not shown) may be added on the first side to balanceweight on two sides.

FIG. 55 is a cross-sectional view of the LED lamp of one embodiment. Asshown in FIG. 55, if further divide upper and lower relationship, on thesame side (either the first side or the second side), heat dissipatingchannel must be considered (here the heat dissipating channel means thefirst heat dissipating channel 7 a), i.e. relationship of air flow zones(not cover electronic components). The second side as an example, afirst quadrant Q1, a second quadrant Q2, a third quadrant Q3 and afourth quadrant Q4 are defined on the second side by an X-axis and aY-axis. The first quadrant Q1, the second quadrant Q2, the thirdquadrant Q3 and the fourth quadrant Q4 communicate with each other. Boththe first quadrant Q1 and the second quadrant Q2 correspond to the lampshell 2, and both the third quadrant Q3 and the fourth quadrant Q4correspond to the heat sink 1. The first quadrant Q1 abuts against thethird quadrant Q3, and the second quadrant Q2 abuts against the fourthquadrant Q4. The X-axis is located on an upper edge of the heat sink 1,and the Y-axis is the central axis shown in the figure.

As shown in FIG. 55, an ideal manner is to place all electroniccomponents on a single side (one side of Y-axis), for example, gatheringin both the second quadrant Q2 and the fourth quadrant Q4, and lowerelectronic components are less than upper electronic components innumber and high heat or heat intolerance electronic components (such astransformers or electrolytic capacitors) are located in the lowerportion. As shown, volume of the electronic components in the secondquadrant Q2 is less than volume of the electronic components in thefirst quadrant Q1 to make an air flow zone (not cover electroniccomponents) shown in the second quadrant Q2 is greater than the firstquadrant Q1 to keep a zone allowing air to rapidly flow. Thus, thesecond side as an example, the ratio of volume of the first channel Siin the second quadrant Q2 to volume of the electronic components in thesecond quadrant Q2 is greater than 3 to make air flow zone in the secondquadrant Q2 have a sufficient size. Of course, a contrary arrangement isalso available, i.e. the ratio of volume of the first channel S1 in thefirst quadrant Q1 to volume of the electronic components in the secondquadrant Q2 is greater than 3.

As abovementioned, volume of the electronic components in the secondquadrant Q2 is less than volume of the electronic components in thefirst quadrant Q1. In an aspect of proportional relationship, a ratio ofvolume of the electronic components in the second quadrant Q2 is lessthan a ratio of volume of the electronic components in the firstquadrant Q1.

As for the arrangement of the lower portion, volume of the electroniccomponents in the fourth quadrant Q4 is less than volume of theelectronic components in the third quadrant Q3, so a sufficient airchannel can be kept from the fourth quadrant Q4 to the first quadrantQ1. In an aspect of proportional relationship, a ratio of volume of theelectronic components in the fourth quadrant Q4 to volume of the firstchannel S1 in the fourth quadrant Q4 is less than a ratio of volume ofthe electronic components in the third quadrant Q3 to volume of thefirst channel S1 in the third quadrant Q3.

If multiple electronic components are categorized to heat-generatingelements, an ideal position of the heat-generating elements is the upperportion, i.e. both the first quadrant Q1 and the second quadrant Q2.Thus, the heat-generating elements are arranged in both the firstquadrant Q1 and the second quadrant Q2. That is, the heat-generatingelements may be in contact with cooling airflow at a distal end of theheat dissipating channel to prevent the cooling airflow from beingheated first not to affect cooling of other electronic components. Theratio of the number of the heat-generating elements in the firstquadrant Q1 corresponding to the heat-generating elements in the secondquadrant Q2 to the number of the heat-generating elements in the secondquadrant Q2 is between 0 and 0.5 to reduce the number of theheat-generating elements on the same cross-section. This is advantageousto enlarging temperature gradient on the same cross-section andradiating heat from the heat-generating elements to surrounding air. Indetail, heat from the heat-generating elements must be radiated to airthrough thermal radiation, and a temperature difference is one of thekey factors. Thus, interference between heat-generating elements must beas less as possible to guarantee the temperature difference betweenheat-generating elements and air to ensure thermally radiativeefficiency.

In the aspect of upward and downward flow of cooling air, volume of thefirst channel in both the third quadrant Q3 and the fourth quadrant Q4is greater than volume of the first channel in the first quadrant Q1 andthe second quadrant Q2 to prevent the cooling airflow from meeting highflow resistance at a starting end not to affect flowing of the coolingairflow.

In general, preferably, the ratio of a cross-sectional area of theelectronic components in a radial direction to a cross-sectional area ofthe heat dissipating channel in a radial direction is between 0 and 0.4,where the ratio 0 means no electronic component on the cross-section,and the ratio 0.4 means avoiding cross-sectional area of the electroniccomponents in a radial direction exceeding half of the heat dissipatingchannel.

On a single side, such as the first side, the ratio of a cross-sectionalarea of the electronic components in the first channel S1 in a radialdirection to a cross-sectional area of the first channel S1 in a radialdirection is between 0 and 0.3. Contrarily, on the second side, theratio of a cross-sectional area of the electronic components in thesecond channel S2 in a radial direction to a cross-sectional area of thesecond channel S2 in a radial direction is between 0 and 0.6. In oneexample, the electronic components on the first side and the second sideadopt different proportion of distribution to make one side have betterflowing of airflow.

As shown in FIG. 54, the abovementioned proportion may be arranged bybiasing the power board 51 from the axis. A biasing distance G is formedbetween the power board 51 and the axis of the heat dissipating channel.The ratio of the biasing distance G to a radius of the heat dissipatingchannel is between 0.15 and 0.4. Such a biasing distance can adjust thecenter of gravity to make the equivalent center of gravity falls on theaxis of the heat dissipating channel.

FIG. 56 is a schematic view of the combination of the power source 5 andthe sleeve 21 of an embodiment. As shown in FIG. 56, the power board 51is configured to incline to the axis of the LED lamp. The side with highflow resistance, such as the side on which more electronic componentsare mounted, may be arranged to be the upward side of the inclined powerboard 51. The side with low flow resistance, such as the side on whichless electronic components are mounted, may be arranged to be thedownward side of the inclined power board 51. As a result, the side withhigh flow resistance still have sufficient airflow to pass. Thecounterweight 52 may be mounted on the downward side of the power board51 according to a tilting status to balance weight on the Y-axis andmake the center of gravity of the LED lamp keep on the Y-axis.

As shown in FIGS. 1, 2, 3 and 4, the lamp shell 2 includes the lamp head23, the lamp neck 22 and the sleeve 21. The lamp head 23 connects to thelamp neck 22 which connects to the sleeve 21. The sleeve 21 is locatedin the heat sink 1 (in the axial direction of the LED lamp, all or mostof the sleeve 21, for example, at least 80% of height of the sleeve 21,does not exceed the heat sink 1). The lamp neck 22 projects from theheat sink 1. Both the sleeve 21 and the lamp neck 22 can providesufficient space to receive the power source 5 and perform heatdissipation, especially for the power source 5 of a high power LED lamp(in comparison with a low power LED lamp, a power source of a high powerLED lamp has more complicated composition and larger size). The powersource 5 is received in both the lamp neck 22 and lamp head 23. Totalheight of the lamp neck 22 and the lamp head 23 is greater than heightof the heat sink 1 so as to provide more space for receiving the powersource 5. The heat sink 1 is separate from both the lamp neck 22 and thelamp head 23 (not overlap in the axial direction, the sleeve 21 isreceived in the heat sink 1). Thus, the power source 5 in both the lampneck 22 and the lamp head 23 is affected by the heat sink 1 slightly(heat of the heat sink 1 would not be conducted to the lamp neck 22 andthe lamp head 23 along a radial direction). In addition, theconfiguration of height of the lamp neck 22 is advantageous to thechimney effect of the first heat dissipating channel 7 a to guaranteeconvection efficiency of the first heat dissipating channel 7 a. Inother embodiments, height of the lamp neck 22 is at least 80% of heightof the heat sink 1 to accomplish the above function. The sleeve 21 ismade of a thermo-isolated material to prevent mutual influence of heatfrom the fins and the power source.

As shown in FIG. 2, the second air inlet 1301 is located in a lowerportion of the heat sink 1 and radially corresponds to an inner side orthe inside of the heat sink 1, i.e. the second air inlet 1301 radiallycorresponds to the inner side or the inside of the fins 11. The innerside or the inside of the fins 11 corresponds to an outer wall (aradially inner side of the fins 11, which nears or abuts against thesleeve 21) of the sleeve 21 of the lamp shell 2. Thus, after convectionair flows into the second air inlet 1301, it flows upward along theouter wall of the sleeve 21 to perform convection and radiallydissipates heat in the inner side or the inside of the fins 11 and theouter wall of the sleeve 21 to implement an effect of thermal isolation.That is, this can prevent heat of the heat sink 1 is conducted from theouter wall of the sleeve 21 to the inside of the sleeve 21 not to affectthe power source 5. From the above, the second heat dissipating channel7 b can not only enhance heat dissipation of the fins 11, but alsoimplement an effect of thermal isolation. Make a positional comparisonbetween the second air inlet 1301 and the LED chips 311, the second airinlet 1301 is located radially inside all of the LED chips 311.

FIG. 57 is an enlarged view of portion B in FIG. 2. As shown in FIG. 57,the lamp head 23 includes a metal portion 231 and an insulative portion232. Wires of the power source 5 penetrates through the insulativeportion 232 to connect with an external power supply. The metal portion231 connects to the lamp neck 22. In detail, as shown in FIG. 58, aninner surface of the metal portion 231 is provided with a thread throughwhich the lamp neck 22 can be screwed on with the metal portion 231.While the metal portion 231 is dissipating heat generated from the powersource 5 in the lamp shell 2 (as described in the above embodiment, atleast part of the inner wall of the metal portion 231 forms a wall ofthe inner chamber of the lamp shell 2, so the thermal conductor directlyconnects with the metal portion 231 and the metal portion 231 can beused for heat dissipation), an outer surface of the metal portion 231 isformed with a projecting structure 2311 as shown in FIG. 58 to addsurface area of the outer surface of the metal portion 231 and enlargeheat dissipating area of the metal portion 231 to increase efficiency ofheat dissipation. As for the power source 5, at least part of the powersource 5 is located in the lamp head 23, and at least part of heatgenerated from the power source 5 can be dissipated through the lamphead 23. The inner wall of the metal portion 231 may also be formed witha projecting structure to add surface area of the inner chamber of thelamp shell 2. In this embodiment, the projecting structure can beimplemented by forming a thread on the inner surface of the metalportion 231.

Next, please refer to FIGS. 59a ˜59 c and FIG. 60. FIG. 59a is aperspective views of the lamp neck 22 of one embodiment, and FIG. 59b isanother perspective view of the lamp neck 22 of this embodiment. FIG. 60is a perspective view of the sleeve 21 of this embodiment. As shown inFIGS. 2, 59 a, 59 b and 60, the lamp neck 22 is connected to the sleeve21 by engagement. In detail, the sleeve 21 has a first positioning unit211 and the lamp neck 22 has a second positioning unit 221. The sleeve21 can be connected with the lamp neck 22 by engaging the firstpositioning unit 211 and the second positioning unit 221.

In this embodiment, the first positioning unit 211 is an engagingportion on the sleeve 21, and the second positioning unit 221 is a latchon the lamp neck 22. The engaging portion can fasten with the latch. Inother embodiments, alternatively, the first positioning unit 211 is alatch on the sleeve 21, and the second positioning unit 221 is anengaging portion on the lamp neck 22. The engaging portion can fastenwith the latch.

In this embodiment, the sleeve 21 has a connecting portion 212. Theconnecting portion 212 includes at least two sheet-shaped bodies 2121 ona circumferential portion of the LED lamp. The first positioning unit211 is formed on the sheet-shaped bodies 2121. When the lamp neck 22engages with the sleeve 21, the second positioning unit 221 is embeddedinto the first positioning unit 211. When embedding, the secondpositioning unit 221 exerts radial pressure to the sheet-shaped bodies2121. When the sheet-shaped bodies 2121 are more than two in number,their radially structural strength would be weakened to make theengagement easier, and the connecting portion 212 would have a largeramount of radial deformation. In this embodiment, the engaging portion212 is a trough or a through hole formed in the sheet-shaped bodies2121.

In this embodiment, two gaps are formed between the two sheet-shapedbodies 2121 and the gaps constitute a positioning trough 213. The lampneck 22 has a third positioning unit (plates 223 and 225) correspondingto the positioning trough 213. When the sleeve 21 engages with the lampneck 22, the third positioning unit (plates 223 and 225) is insertedinto the positioning trough 213 to limit the sleeve 21 to beun-rotatable.

In this embodiment, the connecting portion 212 is coaxially put in thelamp neck 22. By the coaxial connection, both the connecting portion 212and the lamp neck 22 have mutual guiding and supporting effects to makethe connection easy, simple and stable.

In this embodiment, both the lamp neck 22 and the sleeve is anintegrated structure (not shown) to simplify a structure of the lampshell 2.

As shown in FIG. 59 b, the lamp neck 22 has a slot 224 formed betweenplate 223 and plate 225. In detail, the slot 224 allows the power board51 to be inserted for fixture. In this embodiment, two sets of plates223 and 225 are disposed along the axial direction of the LED lamp tomake the LED lamp keep in the axial direction and a gap is kept betweenthe two sets of plates 223 and 225. When the power board 51 has beeninserted into the slot 224, convection can be performed between twosides of the power board 51 through the gap. In this embodiment, whentwo sets of plates 223 and 225 are disposed in the axial direction ofthe LED lamp, the ratio of length L1 of the lower set of plates 223 and225 in the axial direction of the lamp neck 22 to length L2 of the powerboard 51 is 1:14˜22. When the ratio falls within this range and thepower board 51 is inserted into the lower slot 224, two sides of thepower board 51 are limited by the plates 223 and 225, so the power board51 would not tilt to be advantageous to make the power board 51 easy toalign with the other slot 224. This can reduce difficulty in assembling.

In this embodiment, the two plates 223 and 225 are formed by twoparallel ribs. A set of ribs is disposed on an inner wall of the lampneck 22 and extends along the axial direction of the lamp neck 22. Afterthe power board 51 has been inserted into the slot 224, the ribs areparallel to the power board 51.

In this embodiment, the third positioning unit formed by two plates 223and 225, two opposite sides of the positioning trough 213 have effectsof positioning and guiding.

FIG. 59c is a perspective view of the lamp neck 22 on an embodiment. Asshown in FIG. 59c , in some embodiments, the plates 225 are of a singleset along the axial direction of the LED lamp and with longer length.Such a long slot 224 formed the plates 225 can fix the power board 51more firmly. In this embodiment, length of the plate 225 is 15%˜45% oflength of the power board 51 to make the power board 51 held by the slot224.

In other embodiments, the slot 224 may also be a trough on an inner wallof the lamp neck 22 (not shown). Thus, no plate is required forstructural simplification.

As shown in FIGS. 59b and 31, in this embodiment, a first stoppingportion 226 is provided in the lamp neck 22 to correspond to the powerboard 51. When the power board 51 is inserted, it will be stopped by thefirst stopping portion 226 to prevent the power board 51 from beingexcessively pressed and being damaged. On the other hand, the firststopping portion 226 can keep a gap between the power board 51 and anend portion of the lamp head 23 to guarantee convection in the gap.

As shown in FIG. 31, the sleeve 21 has a second stopping portion 215corresponding to the power board 51 for limiting downward movement ofthe power board 51 in the axial direction. Both the first stoppingportion 226 and the second stopping portion 215 limit two sides of thepower board 51 in the axial direction to fasten the power board 51 inthe axial direction.

As shown in FIGS. 1 and 31, the lamp shell 2 has an airflow limitingsurface 214 which extends radially outwardly and is located away fromthe venting hole 222. The airflow limiting surface 214 cloaks at leastpart of the fins 11. When the fins are dissipating heat, hot airflowheated by the part of fins 111 cloaked by the airflow limiting surface214 rises but is blocked by the airflow stopping surface 214 to changeits direction (outward along the airflow stopping surface 214). Thus,rising hot airflow is forced to go away from the venting hole 222. Thiscan prevent hot air from both gathering around the venting hole 222 andaffecting convection speed of the first heat dissipating channel 7 a.Also, this arrangement can prevent rising hot air from both being incontact with the metal portion 231 of the lamp head 23 and affectingheat dissipation of the metal portion 231. Even hot air directly passingthe metal portion 231 to conduct into the inner chamber of the lampshell 2 can also be avoided. The airflow stopping surface 214 may beformed on the sleeve 21. As shown in FIG. 12, in another embodiment ofthe present invention, the airflow stopping surface 214 may also beformed on the lamp neck 22.

As shown in FIG. 31, in this embodiment, upper portions of at least partof the fins 11 in the axial direction of the LED lamp correspond to theairflow stopping surface 214. When the lamp shell 2 is inserted into theheat sink 1, the airflow stopping surface 214 will have a limitingeffect to the lamp shell 2. In this embodiment, the fins abut againstthe airflow stopping surface 214.

As shown in FIG. 31, in this embodiment, the sleeve 21 is made of amaterial whose thermal conductivity is less than that of the material ofwhich the lamp neck 22 is made. The airflow stopping surface 214 isformed on the sleeve 21. Height of the heat sink 1 in the axialdirection does not exceed the airflow stopping surface 214 to reducecontact area between the heat sink 1 and the lamp neck 22. As for thesleeve 21, the lower its thermal conductivity is, the less the heatconducted from the heat sink 1 to the inside of the sleeve 21 is, andthe less the influence to the power source 5 is. As for the lamp neck22, the less the contact area between the lamp neck 22 and the heat sink1 is, the lower the thermal conductivity is. The lamp neck 22 has betterthermal conductivity than that of the sleeve 21. The lamp neck 22 candissipate at least part of heat from the power source 5. In otherembodiments, both the sleeve 21 and the lamp neck 22 may adopt the samematerial, a material with relatively low thermal conductivity, such asplastic.

As shown in FIG. 31, in this embodiment, both a wall of the sleeve 21and a wall of the lamp neck 22 jointly constitute a wall of the innerchamber of the lamp shell 2. Height of the heat sink 1 in the axialdirection does not exceed height of the sleeve 21 to make the heat sink1 corresponds to the sleeve 21 in a radial direction of the LED lamp.That is, the sleeve 21 has an effect of thermal isolation to preventheat of the heat sink 1 from being conducted to the sleeve 21, so thatelectronic components of the power source 5 world not be affected. Allthe lamp neck 22 is higher than a position of the heat sink 1. That is,in a radial direction of the LED lamp, the heat sink 1 does not overlapthe lamp neck 22. This can make thermal conduction between the heat sink1 and the lamp neck 22,and prevent heat from the heat sink 1 to conductto the inside of the lamp neck 22, so that the electronic componentstherein would not be affected. As a result, in this embodiment, heatconducting efficiency of the wall of the sleeve 21 is configured to belower than heat conducting efficiency of the wall of the lamp neck 22.Advantages of such configuration are as follows: (1) because heatconducting efficiency of the sleeve 21 is relatively low, thermalconduction from the heat sink 1 to the sleeve 21 can be reduced toprevent electronic components in the sleeve 21 form being affected bythe heat sink 1; and (2) because thermal conducting from the heat sink 1to the lamp neck 22 does not need to be considered, heat conductingefficiency of the lamp neck 22 can be increased to be advantageous todissipating heat from the electronic components of the power source 5through the lamp neck 22. This can avoid life shortening of the powersource 5 due to overheating. In this embodiment, in order to make heatconducting efficiency of the wall of the sleeve 21 be lower than heatconducting efficiency of the wall of the lamp neck 22, the sleeve 21 ismade of a material with low thermal conductivity and the lamp neck 22 ismade of a material with relatively high thermal conductivity. Toincrease thermal conductivity of the lamp neck 22, the lamp neck 22 maybe provided with a venting hole 222 or a heat conducting portion (notshown) such as metal or other materials with high thermal conductivity.

As shown in FIG. 31, the lamp neck 22 has an upper portion and a lowerportion. The venting hole 222 is located in the upper portion.Cross-sectional area of the upper portion is less than cross-sectionalarea of the lower portion. Airflow speed in the upper portion is fasterthan that in the lower portion, so that initial speed of air ejectedfrom the venting hole 222 can be increased to prevent hot air fromgathering around the venting hole 222. In this embodiment,cross-sectional area of the lamp neck 22 upward tapers off in the axialdirection to avoid obstruction to air flowing. In this embodiment,cross-sectional area of an inlet of the lower portion of the sleeve 21is greater than that of the upper portion of the lamp neck 22.

As shown in FIG. 1, the venting hole 222 of the lamp neck 22 is of astrip shape and extends along the axial direction of the LED lamp.Because of gravity of the LED lamp itself, the lamp neck 22 would sufferan axial pulling force. The venting hole 222 are configured to be of astrip shape extending the axial direction of the LED lamp, so stressconcentration caused by the venting hole 222 in the lamp neck 22 can beprevented. A maximum diameter of an inscribed circle of the venting hole222 is less than 2 mm, preferably, between 1 mm and 1.9 mm. As a result,the venting hole 222 can prevent bugs from entering and prevent mostdust from passing. On the other hand, the vent 41 can keep betterefficiency of air flowing. On the other hand, if the venting hole 222 isconfigured to annular extending along an circumferential portion of thelamp neck 22, then the lamp neck 22 may be deformed by weight of theheat sink 1 to make the venting hole 222 become larger. This would causethat a maximum diameter of an inscribed circle of the venting hole 222is greater than 2 mm, this cannot satisfy the requirement.

As shown in FIG. 21, the venting hole 222 is outside an outer surface ofthe metal portion 231 in radial directions. This can reduce influence tothe metal portion 231 because of rising air ejected from the ventinghole 222 and prevent heat from being conducted back to the lamp shell 2.

FIG. 61 is a cross-sectional view of the LED lamp of another embodiment.FIG. 62 is a schematic view of arrangement of the convection channels inthe LED lamp. As shown in FIGS. 61 and 62, in some embodiments, afundamental structure of the LED lamp is identical to the LED lamp shownin FIG. 1. In some embodiments, the sleeve 21 has an upper portion and alower portion. The upper portion is connected to the lower portionthrough an air guiding surface 216. A diameter of cross-section of theair guiding surface 216 downward tapers off along the axis of the LEDlamp (along the convection direction of the first heat dissipatingchannel 7 a). That is, the air guiding surface 216 can guide air in thesecond heat dissipating channel 7 b toward the radial outside of theheat sink 1 so as to make air be in contact with more area of the fins11 to bring out more heat of the fins 11. The sleeve 21 includes a firstportion and a second portion in the axial direction. The second portionis a part of the sleeve 21 below the air guiding surface 216 (includingthe air guiding surface 216). The first portion is the other part of thesleeve 21 above the air guiding surface 216 (but not including the airguiding surface 216). Electronic components of the power source 5, whichare located in the second portion of the sleeve 21, include heatintolerance elements such as capacitors, especially electrolyticcapacitors so as to make the heat intolerance elements work in lowtemperature environment (near the first air inlet 2201). In otherembodiments, high heat-generating elements may be disposed in the secondportion of the sleeve 21, such as resistors, inductors and transformers.As for the second heat dissipating channel 7 b, when convection airflows into the second heat dissipating channel 7 b and reaches the lowerportion of the sleeve 21, the convection air would lean against theouter wall of the sleeve 21 to rise. This can generate an effect ofthermal isolation, i.e. heat of the fins 11 is prevented from beingconducted to the inside of the sleeve 21 so that the heat intoleranceelements therein would not be affected. When the convection aircontinues to rise, the convection air will flow outward along radialdirections of the fins 11 under the guide of the air guiding surface 216so as to make the convection air be in contact with more area of thefins 11 to enhance an effect of heat dissipation of the fins 11. In thisembodiment, the inner chamber of the sleeve 21 is of awide-upper-side-and-narrow-lower-side channel structure. Thissignificantly enhances the chimney effect and promotes air flowing inthe sleeve 21. In addition, the venting hole 222 can be designed on thelamp neck 22 away from the vent to further improve the chimney effect.

FIG. 63 is a main view of an embodiment of the LED lamp without the heatsink 1. FIG. 64 is an exploded view of FIG. 63. Features mentioned inthis embodiment may be applied to the LED lamp of FIG. 1. As shown inFIG. 63, in some embodiments, an outer wall of the sleeve 21 is providedwith a passage 219 to make part of convection air pass through thepassage 219 to reach the heat sink 1. In this embodiment, the passage219 may be a slot at the lower portion of the outer wall of the sleeve21 or a hole at the lower portion of the outer wall of the sleeve 21.The passage 219 may be multiple in number. The multiple passages 219 areradially distributed on the sleeve 21. At this time, positions of theblocks 217 are correspondingly adjusted.

As shown in FIG. 64, the sleeve 21 is provided with a wire pressingportion 210 downward projecting from a bottom edge of the sleeve 21. Thewire pressing portion 210 is formed with a wire pressing trench 2101 forallowing the wire connecting the power source 5 and the light board 3 tobe embedded into the wire pressing trench 2101 to fix the wire.

As shown in FIG. 64, the sleeve 21 has a fourth positioning unit 2102,and the lamp cover 4 has a fifth positioning unit 46. The fifthpositioning unit 46 corresponds to the fourth positioning unit 2102 tolimit rotation of the sleeve 21 against the lamp cover 4. In detail, thefourth positioning unit 2102 and the fifth positioning unit 46 are apositioning hole and a positioning bar, respectively. The positioningbar is inserted into the positioning hole for engagement. It is notedthat the positioning bar is not arranged in the axial direction of thesleeve 21. Preferably, both the positioning bar and hole are multiple innumber. In other embodiments, the fourth positioning unit 2102 and thefifth positioning unit 46 are a positioning bar and a positioning hole,respectively. The positioning bar is inserted into the positioning holefor engagement.

Next, please refer to FIG. 1, which shows an outline of the LED lamp ofone embodiment. Create a Cartesian coordinate system with the axis ofthe LED lamp as the y-axis, a radial of the LED lamp as the x-axis andthe center of the LED lamp as the origin. A lateral outline of the LEDlamp detours around the axis of the LED lamp 360 degrees to turn aroundto form an contour of the LED lamp (not including the lamp head 23). Anypoint on the outline (usually, the lamp head 23 is a standard one, thus,here does not include the lamp head 23; in detail, the outline iscomposed of the heat sink 1 and the lamp head 22) meets a formula asfollows:

y=−ax3+bx2−cx+K

where K is a constant, range of K is 360˜450, range of a is 0.001˜0.01,range of b is 0.05˜0.3, range of c is 5˜20, preferably, 10˜18, morepreferably, 12˜16.

Hereinafter, as an example, values of a, b and c are supposed asfollows:

y=−0.0012x3+0.2235x2−14.608x+K

where range of K is 360˜450.

The above formula can be interpreted as any point on the outline fallingwithin a range between two lines of y=−0.0012x3+0.2235x2−14.608x+360 andy=−0.0012x3+0.2235x2−14.608x+450.

In sum, comprehensively considering various factors of an effect of heatdissipation, principles of thermodynamics and fluid mechanics,satisfying this formula can obtain a great effect of heat dissipation.

In detail, in one aspect, when any point on the outline satisfy theabove formula, a better match between the LED lamp and a lampshade(especially a conic lampshade) as shown in FIG. 67 can be made. Inanother aspect, when any point on the outline satisfy the above formula,the LED lamp axially tapers off from its bottom to top to make overallwidth of the LED lamp approximately progressively decreases. For theheat sink 1, heat from the LED chips 311 can be rapidly conducted to thelower portion of the heat sink 1 to perform heat dissipation. The upperportion of the heat sink 1 mainly relies upon both radiation andconvection to perform heat dissipation. Thus, the lower portion of theheat sink 1 is configured to have more area to perform thermalconduction (the lower portion of the heat sink 1 has large width andheat dissipating area). For the lamp neck 22, the lamp neck 22 has alarge lower portion and a small upper portion. That is, Cross-sectionalarea of the lamp neck 22 axially upward tapers off. When the lamp neck22 dissipate heat from the power source 5 through convection and theventing hole 222 is located in the upper portion of the lamp neck 22,the rising convection airflow would speed up because of taperedcross-sectional area of the lamp neck 22. This makes the convection airejected from the venting hole 222 have faster initial speed, so ejectedair would rapidly leave away from the venting hole 222 to prevent hotair from gathering near the venting hole 222.

In this embodiment, the outline is a continuous line. In otherembodiments, the outline may be a multiple sectional line (as shown inFIG. 68)

In this embodiment, the outline is a smooth or approximately smoothcurve to avoid forming angles with possibility of cutting hands. On theother hand, this makes convection air flowing along the outside of theLED lamp smoother. In this embodiment, the outline of the LED lamp is asubstantially S-shaped curve including a curve on the lamp neck 22 and acurve on the heat sink 1. It is noted that a junction of the lamp neck22 and the heat sink 1 may form an angle which destroys smoothness ofthe curve. However, in general, overall outline still presents smooth.In addition, LED lamps with the same width, whose outlines are curves,in comparison with a straight line, have more area of an outline surfaceto provide more area for thermal radiation.

As shown in FIG. 66, which shows an outline of the LED lamp of oneembodiment. Create a Cartesian coordinate system with the axis of theLED lamp as the y-axis, a radial of the LED lamp as the x-axis and thecenter of the LED lamp as the origin. A lateral outline of the LED lampdetours around the axis of the LED lamp 360 degrees to turn around toform a contour of the LED lamp (not including the lamp head 23). Theoutline includes an outline of the LED neck 22 and an outline of theheat sink 1.

The lamp neck 22 is used for receiving the power source 5 and primarilyadopts convection to implement heat dissipation to the power source 5.The outline of the lamp neck 22 has a slope a which is a constant. Asshown in FIG. 66, when the outline of the lamp neck 22 is a curve, astraight line may represent an approximate slope of the outline of thelamp neck 22. For example, a line L1 between the top point and thebottom point of the outline of the lamp neck 22 can be used to representan outline of the lamp neck 22 or a line L2 between the center of thetop and the bottom point of the outline of the lamp neck 22 can be usedto represent an outline of the lamp neck 22. In this embodiment, Line L1between the top point and the bottom point of the outline of the lampneck 22 is used to represent an outline of the lamp neck 22 fordescription.

The heat sink 1 primarily adopts conduction to implement heatdissipation to the LED chips 311. The outline of the heat sink 1 has aslope b which is a constant. As shown in FIG. 66, when the outline ofthe heat sink 1 is a curve, a straight line may represent an approximateslope of the outline of the heat sink 1. For example, a line L3 betweenthe top point and the bottom point of the outline of the heat sink 1 canbe used to represent an outline of the heat sink 1 or a line L4 betweenthe center of the top and the bottom point of the outline of the heatsink 1 can be used to represent an outline of the heat sink 1. In thisembodiment, Line L3 between the top point and the bottom point of theoutline of the heat sink 1 is used to represent an outline of the heatsink 1 for description.

In this embodiment, slope a is greater than slope b or an absolute valueof slope a is greater than an absolute value of slope b. Thus, ingeneral, the outline of the lamp neck 22 is steeper than that of theheat sink 1. For the lamp neck 22, under a condition of the same spacerequired for installing the power source 5, in order to guarantee thechimney effect of convection in the lamp neck 22, a certain height ofthe lamp neck 22 must be kept. If a slope of the outline of the lampneck 22 is gentle (small slope), to keep the same height, internalvolume of the lamp neck 22 would increase. However, it is actuallyunhelpful to an installing space of the power source 5. For the heatsink 1, an overall height of the lamp is controlled to guarantee aneffect of heat dissipation. Thus, the heat sink 1 needs to be configuredto be gentle (small slope) to control its overall height. In addition,when the heat sink 1 is gentle (small slope), under a condition of thesame area of heat dissipation, the lower portion of the heat sink 1would have more area for thermal conduction to the LED chips 311.

In this embodiment, slope a is greater than 2, preferably, 2.5˜5, morepreferably, 3˜4, the most preferably, 3.2˜3.8, to make the chimneyeffect of convection in the lamp neck 22 better.

In this embodiment, slope b is smaller than 3, preferably, 1˜2.5, morepreferably, 1.4˜2, the most preferably, 1.5˜1.9, to make the lowerportion of the heat sink 1 have more area for conduction.

In this embodiment, the outline of the Led lamp is a continuous line,i.e. the bottom of the outline of the lamp neck 22 is connected to thetop of the outline of the heat sink 1. In other embodiments, the outlinemay be multiple sectional lines (as shown in FIG. 68). For example, agap is formed between the bottom of the outline of the lamp neck 22 andthe top of the outlie of the heat sink 1. Thus, the overall outline isdiscontinuous.

In this embodiment, the outline of the lamp neck 22 is a concave curve.In one example, if a straight line is connected between the top and thebottom of the outline of the lamp neck 22, then all of the outline ofthe lamp neck 22 is inside the straight line (i.e. the side near theaxis of the LED lamp). The outline of the heat sink 1 is a convex curve.In one example, if a straight line is connected between the top and thebottom of the outline of the heat sink 1, then all of the outline of theheat sink 1 is outside the straight line (i.e. the side away from theaxis of the LED lamp). The outline is a smooth or approximately smoothcurve to avoid forming angles with possibility of cutting hands. On theother hand, this makes convection air flowing along the outside of theLED lamp smoother. In this embodiment, the outline of the LED lamp is asubstantially S-shaped or an inverted S-shaped including a curve on thelamp neck 22 and a curve on the heat sink 1. Both a curve on the lampneck 22 and a curve on the heat sink 1 jointly constitute an S-shaped oran inverted S-shaped curve. It is noted that a junction of the lamp neck22 and the heat sink 1 may form an angle which destroys smoothness ofthe curve. However, in general, overall outline still presents smooth.In addition, the LED neck 22 may be separate from the heat sink 1 (forexample, a certain gap is kept between the lamp neck 22 and the heatsink 1). That is, a curve on the lamp neck 22 and a curve on the heatsink 1 are discontinuous. However, in general, overall outline stillpresents smooth. The outline of the lamp neck 22 is a concave curve, soin the downward section, an enlarging extent of the lamp neck 22increases in size to make the final bottom of the lamp neck 22 have alarger size to connect with the heat sink 1. In one example, an initialposition of the upper portion of the heat sink 1 may obtain a largersize. The outline of the heat sink 1 is a convex curve, so in the upwardsection, a reducing extent of the heat sink 1 increases in size to makethe size reduction of the lower portion of the heat sink 1 becomegentler and gentler. Thus, the lower portion have larger area of theheat sink 1 for heat dissipation. In other embodiments, the outline ofthe lamp neck 22 may be a straight line and the outline of the heat sink1 is a curve. In addition, the straight line may be parallel to the LEDlamp. In other embodiments, both the outline of the lamp neck 22 and theoutline of the heat sink 1 are straight lines or multiple sectionallines.

In this embodiment, any point on the outline of the lamp neck 22 mustmeet a formula as follows:

y=−ax+k1+h,

where k1 is a constant and h is height of the heat sink 1.

any point on the outline of the heat sink 1 must meet a formula asfollows:

y=−bx+k2,

where k2 is a constant.

In this embodiment, when overall width of the LED lamp is configured tobe between 100 mm and 220 mm, k1 is 100˜200 and k2 is 100˜200. Forexample, when maximum overall width of the LED lamp is 200 mm, k1 is140˜150 and k2 is 170˜200.

In this embodiment, height of the lamp neck 22 is greater than 80% ofheight of the heat sink 1. Because the lamp neck 22 is axially separatefrom the heat sink 1 without overlapping, the power source 5 in the lampneck 22 is less affected by the heat sink 1. Thus, when height of thelamp neck 22 is greater than 80% of height of the heat sink 1, morespace for installing the power source 5 can be obtained and the powersource 5 is less affected by the heat sink 1. In addition, when heat ofthe power source 5 in the lamp shell 2 is dissipated by convection,configuration of height of the lamp neck 22 can guarantee height of thelamp shell 2 to guarantee the chimney effect of convection of heatdissipation.

As shown in FIG. 69, which shows the outline of the LED lamp. Create aCartesian coordinate system with the axis of the LED lamp as the y-axis,a radial of the LED lamp as the x-axis and the center of the LED lamp asthe origin. A lateral outline of the LED lamp detours around the axis ofthe LED lamp 360 degrees to turn around to form a contour of the LEDlamp (not including the lamp head 23). The outline includes an outlineof the lamp neck 22 and an outline of the heat sink 1. As shown in FIG.69, in this embodiment, the outline of the LED lamp includes a firstcurved surface and a second curved surface. Both the first curvedsurface and the second curved surface jointly constitute a curvedsurface of the outline of the LED lamp. The first curved surfaceincludes the curved surface of the outline of the lamp neck 22 or thecurved surface of both the outline of the lamp neck 22 and the outlineof part of the heat sink 1. The second curved surface include the curvedsurface of the outline of the heat sink 1 or the curved surface of theoutline of part of the heat sink 1.

In this embodiment, the outline of the lamp neck 22 is a smooth orapproximately smooth curve and the outline of the heat sink 1 is asmooth or approximately smooth curve to avoid forming angles withpossibility of cutting hands. On the other hand, this makes convectionair flowing along the outside of the LED lamp smoother. In thisembodiment, the radius of curvature of the outline of the lamp neck 22is greater than the radius of curvature of the outline of the heat sink1. It is noted that the phrase “the radius of curvature of the outlineof the lamp neck 22 is greater than the radius of curvature of theoutline of the heat sink 1” means that the radius of curvature of 60% ofthe outline of the lamp neck 22 being greater than the radius ofcurvature of 60% of the outline of the heat sink 1 can be deemed as theradius of curvature of the outline of the lamp neck 22 being greaterthan the radius of curvature of the outline of the heat sink 1.

As shown in FIG. 69, in this embodiment, a radius of curvature of theoutline of the lamp neck 22 is 120 mm˜3000 mm, preferably, 150 mm˜200mm, more preferably, 160 mm˜190 mm, and the most preferably, 170 mm˜185mm. A radius of curvature of the outline of the heat sink 1 is 30 mm˜150mm, preferably, 70 mm˜130 mm, more preferably, 80 mm˜120 mm, and themost preferably, 90 mm˜110 mm. Based on the abovementioned, if at least60% of the radius of curvature falls in the range or curvature of acurve which is the most consistent with the outline can be deemed as theradius of curvature of the outline of the lamp neck 22 and the heat sink1. For example, if a radius of curvature of at least 60% of the outlineof the lamp neck 22 is 180 mm, then the radius of curvature of the lampneck 22 can deemed as 180 mm. Based on the abovementioned, it can alsobe interpreted that a curve similar to an outline can representcurvature of the outline. That is, an outline itself may not be a curve.In some embodiments, considering overall width of the LED lamp, theoutline of the lamp neck 22 and the outline of the heat sink 1 areseparately related to overall width of the LED lamp. If width of the LEDlamp (a size of the widest portion of the LED lamp) is L, then theradius of curvature of the outline of the lamp neck 22 is 0.6 L˜15 L,preferably, 0.75 L˜L, more preferably, 0.8 L˜0.95 L, and the mostpreferably, 0.85 L˜0.925 L; and the radius of curvature of the outlineof the heat sink 1 is 0.15 L˜0.75 L, preferably, 0.35 L˜0.65 L, morepreferably, 0.4 L˜0.6 L, and the most preferably, 0.45 L˜0.55 L. Thatis, both curvature of the outline of the lamp neck 22 and curvature ofthe outline of the heat sink 1 vary with change of overall width of theLED lamp. In some embodiments, if an outer diameter of the largestportion of the lamp neck 22 is R, then curvature of the outline of theheat sink 1 must be greater than L/2-R/2 to guarantee both the heat sink1 having sufficient height and the chimney effect of the second heatdissipating channel 7 b.

In this embodiment, a center angle c occupied by the outline of the lampneck 22 is 10˜50 degrees, preferably, 20˜35 degrees, and morepreferably, 25˜30 degrees, to guarantee both the lamp neck 22 havingsufficient height and the chimney effect of convection in the lamp neck22.

In this embodiment, a center angle d occupied by the outline of the heatsink 1 is 40˜120 degrees, preferably, 55˜90 degrees, more preferably,65˜80 degrees, and the most preferably, 70˜75 degrees, to controloverall height of the heat sink 1.

As shown in FIG. 70a , which is a schematic view of the combination ofthe LED lamp and a lampshade of one embodiment. In this embodiment, thelampshade 6 has a receiving room 61 in which the LED lamp isaccommodated. A lower portion of the receiving room 61 is open to allowthe LED lamp to be installed into the receiving room 61 from the lowerportion of the lampshade 6. After heat from the LED lamp is diffused tothe receiving room 61, and then dissipated outward through the openingby air convection. In this embodiment, when heat of the LED lamp isbeing dissipated, part of heat is directly delivered to the lampshade 6by thermal radiation and the lampshade 6 further delivers the heat tothe outside. Another part of heat is delivered to air between thelampshade 6 and the LED lamp by conduction and convection, and thendelivered to the outside of the lampshade 6 by convection, conduction orradiation.

As shown in FIG. 70b , which is a schematic view of the combination ofthe LED lamp and an embodiment of a lampshade 6, in this embodiment, thelampshade 6 is formed with a convection hole 62 located at an upperportion thereof, such that when heat from the LED lamp is delivered toair in the receiving room 61, the air would flow upward to pass throughthe convection hole 62 to bring out the hot air.

As shown in FIG. 70c , which is a schematic view of the combination ofthe LED lamp and an embodiment of a lampshade 6, in this embodiment, thelampshade 6 has a closed receiving room 61. After the LED lamp has beeninstalled in the receiving room 61, because of isolation with theoutside, it would have a dust-proof effect to prevent dust fromaccumulating inside or outside the LED lamp. After heat from the LEDlamp is delivered to air in the receiving room 61, the air circles roundin the receiving room 61, then is delivered to the lampshade 6, andfinally delivered to the outside through the lampshade 6.

In this embodiment, the lampshade 6 may be made of a metal or plasticmaterial. The former is advantageous to heat dissipation, and the latterwould make weight and cost become light and low, respectively. Also, aplastic lampshade may be configured to be light-permeable. When thelampshade 6 is closed, for a better effect of heat dissipation, a metalmaterial is preferred.

FIG. 65a is an exploded view of the lamp shell of the LED lamp ofanother embodiment with a different lamp shell 20. FIG. 65b is aschematic assembling view of FIG. 65a . FIG. 65c ˜65 d are explodedviews of the LED lamp. FIG. 65e is a cross-sectional view of the LEDlamp of FIG. 65a . As shown in FIGS. 65a, 65b and 65c , in someembodiments, the lamp shell 20 includes a lamp head 230, a lamp neck 220and a sleeve 210. The lamp head 230 is screwed with the lamp neck 220.The lamp neck 220 connects to the sleeve 210. The sleeve 210 connects tothe heat sink 10. In detail, a circumferential edge of the lamp neck 220is formed with a breach 2230. A protruding bar 2110 on the sleeve 210corresponds to the breach 2230. The sleeve 210 is pushed toward the lampneck 220 and then rotate the lamp neck 220 to fasten with the sleeve210. The heat sink 10 is formed with a positioning trench 1210 locatedon an inner wall of a heat dissipating post 120. An engaging trough 2140is formed on an inner wall of the sleeve 210. The power board 510 isembedded into the engaging trough 2140 to be secured. The number of theengaging trough 2140 depends on shapes of the power board 510. Forexample, when the power board 510 is of a two-dimensional shape, thenumber of the engaging trough 2140 is two. In addition, in anotherembodiment of the present invention, the engaging trough 2140 may beconfigured to be rib-like. Two parallel or perpendicular ribs formed onan edge of an inner wall of the sleeve 210 can fix the power board 510in the sleeve 210, but limited to this. The power source 50 may furtherinclude other electronic components such as transformers, capacitors,resistors, inductors, fuses, MOSFETs, etc. When the power board 510 isinserted into the sleeve 210, the power source 50 would heat up. Whenheat-generating elements such as transformers, capacitors or MOSFETs arelocated near the bottom end of the sleeve in layout, i.e. in comparisonwith other electronic components, these heat-generating elements arerelatively adjacent to the inlet of airflow channel of the heat sink 10.Because when these heat-generating elements are relatively adjacent tothe bottom end of the heat sink 10, the path through which cool airflows to these heat-generating elements is the shortest, heatdissipation to the heat-generating elements can be effectivelyimplemented to reduce temperature in the chamber of the lamp shell 20and to improve working stability of the LED lamp. The sleeve 210 isdisposed with a positioning bar 2120 corresponding to the positioningtrench 1210 of the heat sink 10. The positioning bar 2120 is insertedinto the positioning trench 1210, and the sleeve 210 is pushed towardthe heat sink 10 to fasten the sleeve 210 to the heat sink 10.

As shown in FIGS. 65a ˜65 e, when assembling the LED lamp, the lamp head231 is screwed up with the lamp neck 220 first, then the power board 510is inserted into the engaging trough 2140, the lamp neck 220 connects tothe sleeve 210, the positioning bar 2120 is inserted into thepositioning trench 1210 of the heat sink 10 to make the sleeve 210pushed to the bottom of the central chamber of the heat sink 1, andfinally, the light board 3 is fixed on the heat sink 1 by riveting tofasten the lamp cover 40 to the heat sink 10. When assembling, theinvention adopts detachable engagement to simplify assembling anddisassembling with guaranteeing connective strength, no part will bedamaged when assembling and disassembling, all parts can be repeatedlyused to solve the drawbacks of conventional screwing connection,including time consuming, high labor cost and high damage rate inassembling and disassembling parts.

As shown in FIG. 65c , the fins include first fins 1110 and second fins1120. The first fins 1110 interlace with the second fins 1120 at regularintervals. Each second fin 1120 has a connecting notch 150correspondingly engaging with a connecting bar 2130 of sleeve 210 toenhance connective strength between the sleeve 210 and the heat sink 10.

As shown in FIGS. 65c and 65b , the sleeve 210 is of a substantiallyhollow cylindrical shape. The inner chamber of the sleeve 210 is achannel formed by a wide upper portion and narrow lower portion (thelower portion of the sleeve 210 is less than the upper portion thereofin cross-sectional area). The ratio of height to width of the wholesleeve 210 is greater than 2.5 to make the chimney effect moreeffective, preferably, the ratio is 2.5˜10. According to the standardsof the most common A19, A20 and A67 bulb lamps, overall height H of thesleeve 210 may be 40˜80 mm. Such awide-lower-portion-and-narrow-upper-portion structure can enhance thechimney effect to promote air convection in the sleeve 210. A top end ofthe sleeve 210 is connected to a top flowing passage of the lamp neck220. When heat in the sleeve 210 gathers to the top thereof, the heatwould flow to the venting hole 2220 of the lamp neck 220 through the topflowing passage, and then be ejected from the lamp shell 20 toaccomplish heat dissipation. The above-mentioned specification of thesleeve 210 is merely an exemplar embodiment and cannot be limited tothis.

The heat dissipating method of the LED lamp:

In this embodiment, the heat dissipating method of the LED lamp includesheat dissipation to both the LED chips 311 and the power source.

As shown in FIGS. 1, 4 and 6, the heat dissipating method for the LEDchips 311 (heat from the working LED chips 311) includes the followingsteps:

S101: providing a light board 3 on which the LED chips 311 are mountedfor conducting at least part of heat from the LED chips 311 to the lightboard 3 by thermal conduction; and

S102: providing a heat sink 1 on which the light board 3 is mounted forconducting at least part of heat from the LED chips 311 to the heat sink1 through the light board 3 by thermal conduction and radiating theheated air from the heat sink 1 to the outside by convection;

The step S102 further includes:

a) The heat sink 1 is provided with fins 11. The heat sink 1 includes asecond heat dissipating channel 7 b with a second air inlet 1301.Convection air flows into the second air inlet 1301 to enter spacesbetween the fins 11 to bring out heat radiated from the fins 11 to air.The second air inlet 1301 is located in the lower portion of the heatsink 1.

b) The heat sink 1 is provided with a third heat dissipating channel 7 cformed between adjacent two of the fins 11 or between two sheetsextending from a single fin 22. A radially outer portion between twofins 11 forms an intake of the third heat dissipating channel 7 c. Airflows into the third heat dissipating channel 7 c through the radiallyouter portion of the LED lamp to bring out heat radiated from the fins11 to air.

As shown in FIG. 21, in this embodiment, at least one fin 11 is dividedinto two portions in a radial direction of the LED lamp, and the twoportions are arranged at an interval in a radial direction of the LEDlamp so as to form a passage. When the LED lamp is working, convectionair may perform thermal convection in the interval to improve efficiencyof convection.

When heat dissipation is performed to the LED chips 311, preferably,20˜30 square mm of heat dissipating area of the heat sink per watt ofthe LED lamp is configured to obtain a balance between an effect of heatdissipation to the LED chips 311 and both volume and weight of the heatsink 1. This can control both volume and weight of the heat sink 1 underguaranteeing an effect of heat dissipation. In this embodiment, to makethe lampshade have more area for heat dissipation, weight of the heatsink 1 is set to occupy above 50% of overall weight of the LED lamp,preferably, 55%˜65%; and volume of the heat sink 1 is set to occupyabove 20% of overall volume of the LED lamp, preferably, 25%˜50%.

As shown in FIG. 40, when heat from the LED chips 311 is beingdissipated, a projection (projected onto the plane on which the LEDchips 311 are mounted) of at least part of fins 11 in the heightdirection (axial direction) is in contact with at least one LED chip311. That is, in the height direction (axial direction), a projection ofat least part of the fins 11 is superposed or overlapped with at leastone LED chip 311. Thus, a heat conducting path of the LED chips 311 canbe shortened to reduce thermal resistance and to be advantageous tothermal conduction. Preferably, a projection (projected onto the planeon which the LED chips 311 are mounted) of any fin 11 in the heightdirection (axial direction) is in contact with at least one LED chip311.

As shown in FIGS. 1 and 29, when heat from the LED chips 311 is beingdissipated, the light board 3 has an inner border 3002 and an outerborder 3003. Both the inner border 3002 and the outer border 3003 extendupward along the axial direction of the LED lamp to form a region. Areaof part of the fins 11 inside the region is greater than area of anotherpart of the fins 11 outside the region. As a result, most of the fins 11correspond to the light board 3 to enhance utilization rate of the fins11 and increase effective heat conducting area of the fins 11 for theLED chips 311.

As shown in FIG. 4, the method for dissipating heat of the working powersource includes the following steps:

S201: providing a lamp shell 2 having a first heat dissipating channel 7a in which the power source 5 is disposed, wherein the first heatdissipating channel 7 a has a first air inlet 2201 and a venting hole222; and

S202: convection air flowing into the first heat dissipating channel 7 athrough the first air inlet 2201, wherein heat from the power source 5is radiated to surrounding air, and heated air is ejected from theventing hole 222 by convection to prevent the power source 5 fromworking in high temperature environment.

As shown in FIG. 22, at least one heat-generating element 501 (aresistor, an inductor, a transformer or a rectifier) is arranged at aposition in the first heat dissipating channel 7 a near the lamp head23. In a projection of in a direction perpendicular to the axis of theLED lamp, heat from at least one heat-generating element 501 isdelivered to the lamp head 23 by thermal conduction or thermal radiationand the heat of the lamp head 23 is dissipated to air or the socketconnected thereto.

In other embodiments, at least one heat-generating element 501 is inthermal contact with the lamp head 23, at least one heat-generatingelement 501 is located in the lamp head 23, the heat-generating element501 is in contact with the lamp head 23 through a thermal conductor 53,and the heat-generating element 501 is fastened to the lamp head 23through the thermal conductor 53. As a result, the thermal conductor 53can not only conduct heat to the lamp head 23, but also fasten theheat-generating element to prevent the heat-generating element fromloosening.

As for design of heat dissipation of the power source 5, a position ofat least one heat-generating element in the axial direction of the LEDlamp is higher than a position of the venting hole 222. Most heat fromthe heat-generating element 501 higher than the venting hole 222 isdissipated through the lamp head or other ways.

In addition, at least one heat-generating element and otherheat-generating elements are mounted on different sides of the powerboard 51 so as to make convection air bring out heat from theheat-generating elements to surrounding air along these two sides.

The assembling method of the LED lamp is described as follows.

As shown in FIG. 2, in an embodiment, the method includes the followingsteps:

S301: providing a light board 3 on which the LED chips 311 are mounted;

S302: providing the heat sink 1;

S303: providing the power source 5;

S304: providing the lamp shell 2;

S305: installing the power source 5 in the lamp shell 2;

S306: installing the lamp shell 2 on the heat sink 1 and electricallyconnecting the power source 5 with the light board 3; and

S307: providing a lamp cover 4 and fastening the lamp cover 4 on theheat sink 4 to cover the light board 3.

The order of the above steps can be adjusted according to actualrequirements. After the step S304, the light board 3 is attached on theheat sink 1 to form an integrated body.

In the step S304, providing the lamp shell 2, the lamp head 23 and thelamp neck 22 are provided with corresponding threads to allow the lamphead 23 to screw with the lamp neck 22 to implement connection.

In the step S307, the sleeve 21of the lamp shell 2 is detachably engagedwith the heat sink 1. Here, after the lamp shell 2 has been assembled,the sleeve 21 with the lamp shell 2 as a whole connects to the heat sink1. In an embodiment of the present invention, the sleeve 21 is connectedto the heat sink 1 first, and then the other elements of the lamp shell2 are fixed to the sleeve 21, i.e. the lamp neck 22 is connected to thesleeve 21.

As shown in FIGS. 31 and 60, the heat sink 1 has a center hole and thesleeve is formed with a block 217 on a surface thereof. The block 217has a first limiting side 2171 disposed and corresponding to an edge ofouter surface of the sleeve 21. A distance between two fins 11 in aradially inner portion is greater than a width of the block 217. Whenthe sleeve 21 in inserted into the center hole of the heat sink 1, theblock 217 aligns with an interval between two fins 11 to be insertedinto the heat sink 1 until the first limiting side 2171 exceeds thebottom of the fins 11 in the axial direction of the LED lamp. At thistime, rotate the sleeve 21 to make the first limiting side 2171 abutagainst the bottom of the fins 11. In addition, the sleeve 21 may have asecond limiting side 218. When the first limiting side 2171 abutsagainst the bottom of the fins 11, the second limiting side 218 abutsagainst the top of the fins 11. As a result, the sleeve 21 is connectedto the heat sink 1 without any other external elements such as screws.When disassembling, reverse the above steps.

Preferably, the sleeve 21 is provided with a third limiting side 2172 ata side of the block 217 in a circumferential direction for limitingrotation of the fins 11. When the sleeve 21 is installed to the heatsink 1, the block 217 aligns with an interval between two fins 11 to beinserted into the heat sink 1 until the first limiting side 2171 exceedsthe bottom of the fins 11 in the axial direction of the LED lamp. Atthis time, rotate the sleeve 21 to make the first limiting side 2171abut against the bottom of the fins 11 and keep rotating until a lateralside of the fins 11 abuts against the third limiting side 2172 to avoidover-rotation which causes dislocation between the first limiting side2171 and the fins 11.

As shown in FIGS. 59a ˜59 b and 60, the sleeve 21 has a firstpositioning unit 211 and the lamp neck 22 has a second positioning unit221. The first positioning unit 211 engages with the second positioningunit 221. In detail, the first positioning unit 211 is an engagingportion on the sleeve 21 and the second positioning unit 221 is a latchon the lamp neck 22.

As shown in FIGS. 31˜33, in the step S308, the lamp cover 4 is providedwith a latch 46 and the heat sink 1 is provided with a holecorresponding thereto. The lamp cover 4 is fastened to a back 134 of thebase 13 of heat sink 1 by inserting the latch 46 into the hole.

FIG. 71 is a layout diagram of the LED module of an embodiment. FIG. 72is an enlarged view of portion D in FIG. 71. FIG. 73 is an enlarged viewof the LED module of another embodiment. The LED modules shown in bothFIGS. 71 and 72 may be applied to the LED lamp of FIG. 1. As shown inFIGS. 71˜73, the LED module 70 includes at least one LED unit 710. TheLED units 710 are two or more in number and electrically connected inparallel. Each LED unit 710 includes at least one LED 711. When an LEDunit 710 includes multiple LEDs 711, the LEDs 711 in the same LED unit710 are electrically connected in series. A positive terminal of thefirst LED 711 is coupled to a positive terminal of the LED unit 710. Anegative terminal of the first LED 711 is coupled to next or a secondLED 711. A positive terminal of the last LED 711 is coupled to anegative terminal of a former LED 711. A negative terminal of the lastLED 711 is coupled to a negative terminal of the LED unit 710.

As shown in FIG. 71, in some embodiments, the LED module 70 includesfive LED units 710. As shown in the figure, the LED module 70 aredistributed on two circumferences, i.e. an inner circumference and anouter circumference. The inner circumference is disposed with twocomplete LED units 710, and the outer circumference is disposed with twocomplete LED units 710, too. As for the fifth LED unit 710, most LEDs611 thereof are located on the outer circumference and a few thereof arelocated on the inner circumference. That is, the LEDs 711 of the fifthLED unit 710 on the inner circumference is less than the LEDs 711 on theouter circumference.

As shown in FIG. 73, in some embodiments, the LED module 70 includes tenLED units 710. In the shown embodiment as an example, the LED module 70is distributed on three circles, i.e. an inner circle, a middle circleand an outer circle. There are two, four and three complete LED units710 on the inner circle, the outer circle and the middle circle,respectively. Most of the tenth LED unit 710 is mounted on the innercircle, and a few of the tenth LED unit 710 is mounted on the outercircle. That is, the LEDs 711 of the tenth LED unit 710 on the innercircle are greater than the LEDs 711 of the tenth LED unit 710 on theouter circle in number.

Preferably, the number of the LEDs 711 of the LED unit 710 is 10˜20,more preferably, 12˜16.

As shown in FIGS. 71, 72 and 73, the LEDs 711 are mounted on the lightboard 3 along a circumferential direction of the light board 3. When theLEDs 711 of the same LED unit 710 are on the same circle, all LEDs 711are connected by a first wire 712. That is, connecting in series of theLEDs 711 on the same circle is implemented by the first wire 712. If theLEDs 711 of the same LED unit 710 are divided into two groups, one groupis located on a circle and the other group is located on another circle,then the LEDs 711 of the same LED unit 710 on the same circle areconnected by the first wire 712, and the LEDs 711 of the same LED unit710 on another circle are connected by a second wire 713. The secondwire 713 is less than the first wire in width to provide a better layoutfor the LEDs 711. If width of the second wire 713 is excessively wide,then pitch of the LEDs 711 on the corresponding circle would be affectedto become larger than the others.

As shown in FIGS. 71, 72 and 73, width of the first wire 712 is at leastgreater than width of the LEDs 711 (LED chips 311). The first wire 712adopts a metal material with great thermal conductivity to beadvantageous to heat dissipation of the LEDs 711 (LED chips 311).Because width of the first wire 712 is at least greater than width ofthe LEDs 711 (LED chips 311), it is more advantageous to installation ofthe LEDs 711 and forming electrical connection with the first wire.

As shown in FIGS. 71, 72 and 73, the LEDs 711 are distributed ondifferent circles on the light board. That is, there are at least twocircles for mounting LEDs 711. The two circles are approximatelyconcentric. The LEDs 711 on the innermost or the outermost circle areconnected in series by the first wire 712. At least part of the firstwire 712 connecting the LEDs 711 on the innermost or the outermostcircle is greater than the other part thereof in width. Because no LED711 is mounted outside the outermost circle or inside the innermostcircle, width of the first wire 712 connecting the LEDs 711 on theinnermost or the outermost circle has no limit. Thus, the first wire 712connecting the LEDs 711 on the innermost or the outermost circle may beprovided with an extension portion 7121 on a radial outside or inside toincrease its width and area. This is advantageous to be heatdissipation. FIG. 73 as an example, it has three circles for mountingthe LEDs 711, wherein width of the first wire 712 on the innermost oroutermost circle is greater than width of the first wire 712 on themiddle circle.

As shown in FIGS. 71 and 72, the light board 3 is provided with fixingholes 301. The light board 3 is fastened onto the base 13 by insertingscrews or rivets into the fixing holes 301. The fixing holes occupy somearea, so parts of the first wire 712 corresponding to the fixing holes712 must detour around the fixing holes 301. And width of thesedetouring parts of the first wire 712 is less than width of the firstwire 712 with the extension portion 7121 so as to reduce extent ofdetour of the first wire 712.

As shown in FIGS. 71 and 72, in a direction perpendicular to the lightboard 3, area of a single LED 711 is M1, and area of part of the firstwire 712 encompassed by a projection of a single LED 711 projected ontothe light board 3 is M2, which satisfies the following relationship:M2:M1=1:(0.85˜0.96), preferably, M2:M1=1:(0.9˜0.96), so as to make theLEDs 711 be able to correspond to more area of the first wire 711 forheat dissipation.

As shown in FIGS. 71 and 72, different LED units 710 are coupled by athird wire 714. The third wire 714 connects positive electrodes of thefirst LEDs 711 of two different LED units 710 or the third wire 714connects negative electrodes of the last LEDs 711 of two different LEDunits 710. The third wire 714 is less than the first wire 712 in width.

As shown in FIGS. 71 and 72, the LED module 70 includes two electrodeterminals such as the positive terminal 701 and the negative terminal702. Both the positive terminal 701 and the negative terminal 702 arelocated radially inside all of the LEDs 711, the first wire 712, thesecond wire 713 and the third wire 714. In other embodiments,alternatively, both the positive terminal 701 and the negative terminal702 are located radially outside all of the LEDs 711, the first wire712, the second wire 713 and the third wire 714. Both the positiveterminal 701 and the negative terminal 702 are used to connect with thepower source 5. In addition, both the positive terminal 701 and thenegative terminal 702 have different shapes for distinction.

As shown in FIGS. 74 to 82, the present disclosure provides a powersupply module for LED lamp. The power supply module includes input ends(ACN, ACL) for receiving AC driving signal; a first rectifying circuit100 for converting the AC driving signal into rectified signal; afiltering 200 for converting the rectified signal into filtered signal;a power converter 400 for converting the filtered signals into powersignal which is capable of lighting up an LED light source 500; and abias generating circuit 600 electrically connected to the input ends(ACN, ACL) and the power converter 400 for performing buck-conversion tothe AC driving signal to generate a working voltage of the powerconverter 400.

In the power supply module of certain embodiments, the bias generatingcircuit 600 performs buck-conversion to the AC driving signal andconverts the AC driving signal into a working voltage of the powerconverter 400. The working voltage is provided to the power converter400 so that the power converter 400 can drive the LED light source 500to emit light. It can be seen that, by utilizing the bias generatingcircuit 600 to perform active power conversion to externally input ACdriving signal, to the working voltage can be generated rapidly generatethe so as to effectively improve starting speed of an LED lamp.

When using the power supply module as shown in FIGS. 75 to 82, startingspeed of HID-LED can be reduced to be about 60 ms, which possesses avery high value of application and very great experience of using.

The power supply module can be applied to high power LED lamps. Outputpower of the power converter 400 may be above 30 W. As shown in FIG. 2,the input ends (ACN, ACL) may be two ends of the power supply module: afirst end ACL and a second end ACN. The AC driving signal is inputthrough the two ends. The AC driving signal may be AC signal of 220V orany other voltage values. Of course, the input ends (ACN, ACL) may havemore than two ends, for example, four ends. It is not limited as long asAC power can be input.

In this embodiment, the first rectifying circuit 100 may be a bridgerectifier. As shown in FIG. 76, which is a circuit diagram of arectifying circuit and a filtering circuit of an embodiment of theinvention, the first rectifying circuit 100 includes diodes D7, D8, D9and D10. The first rectifying circuit 100 performs full waverectification to the AC driving signal to generate DC driving signal (DCpower).

In detail, as shown in FIG. 76, anodes of diodes D7, D9 are electricallyconnected to a first end of the filtering circuit 200, cathodes ofdiodes D7, D9 are electrically connected to anodes of diodes D8, D10,and cathodes of diodes D8, D10 are electrically connected to a secondend of the filtering circuit 200. Contacts of diodes D7 and D8 areelectrically connected to the first end ACL. A cathode of diode D8 iselectrically connected to a cathode of diode D10. Contacts of diodes D9and D10 are electrically connected to the second end ACN.

In addition, the first rectifying circuit 100 may also be any othertypes of full wave rectifier or half wave rectifier, which can alsoaccomplish the desired function.

In this embodiment, the filtering circuit 200 includes capacitors C1, C2and an inductor L1. Frist ends of both capacitor C1 and inductor L1serve as the second end of the filtering circuit 200 to electricallyconnect with cathodes of diodes D8 and D10. The second end of inductorL1 is electrically connected to the first end of capacitor C1. Thesecond ends of capacitors C1 and C2 serve as the first end of thefiltering circuit 200 to electrically connect with anodes of diodes D7and D9. The filtering circuit 200 receives the DC power (the rectifiedsignal) rectified by the first rectifying circuit 100 and filters highfrequency components of the DC power. The DC power filtered by thefiltering circuit 200 is a relatively flat DC waveform. The filteredsignal is sent to a post-stage circuit through connecting ends 30 land302.

In some embodiments, the filtering circuit 200 may include onlycapacitor C1 to implement filtration without affecting the desiredfunction of the invention.

An electro-magnetic interference (EMI) reduction circuit 900 may bedisposed between the input ends (ACN, ACL) and the rectifying circuit100. The EMI reduction circuit 900 can reduce influence to the drivingsignal from an interference magnetic field. In the EMI reduction circuit900, a power line (including a main line and/or a branch of the mainline) electrically connected to two ends of the input ends ACN, ACL iselectrically connected with an excitation coil LF2 connecting a resistorbranch (e.g. a branch at which resistor R1 is located) and capacitorbranches (e.g. branches at which capacitors CX1, CX2, CX3 are located),and separately electrically connecting inductor Li1, Li2 at twobranches.

Of course, the EMI reduction circuit 900 may adopt an EMI filter havingmultiple filtering elements. In detail, the EMI filter has differentialmode capacitors, common mode inductors, and common mode capacitors.

In this embodiment, the power converter 400 converts the filtered signalinto an electrical signal which is capable of lighting up the LED lightsource 500. The power converter 400 may change voltage level of thefiltered signal to generate DC driving signal with target voltage value.The power converter 400 has an output end for outputting DC drivingsignal with target voltage values.

In addition, the branch electrically connected to the input ends ACN,ACL may further be connected with a fuse F1 in series. The fuse F1 maybe a current fuse or a temperature fuse.

FIG. 78 is a circuit diagram of a power converter of an embodiment ofthe invention. As shown in FIGS. 74 and 78, the power converter 400receives signal from a pre-stage circuit through the connecting end 401,402, and the power signal are provided to a post-stage through theconnecting ends 5001, 5002. The power converter 400 may adopt a PWM(Pulse Width Modulation) circuit, which controls pulse width to outputtarget signal. In detail, the power converter 400 includes a controllerU2, a power switch Q2, a transformer T2 and a diode D10. Controller U2,power switch Q2, diode D10 and an energy storage coil (a coil of thetransformer T2, which is electrically connected between the power switchQ2 and the connecting end 5002) cooperate to output power signal (DCdriving signal) with required voltage and/or current. The controller U2is activated by a working voltage VCC provided by the bias generatingcircuit 600 to output PWM control signal to control switching of thepower switch Q2, so that the energy storage coil repeatedly charge anddischarge in response to the switching state of power switch and thecontinuity of the current can be maintained through diode D4 (which isoperated as a flyback diode), and thus generate the required powersignal between the connecting ends 5001, 5002.

Power switch Q2 may be a MOSFET. A first end (power end) of controllerU2 electrically connects to an output end of the bias generating circuit600. A second end of controller U2 electrically connects to an end oftransformer T2. An end of the energy storage coil of transformer T2electrically connects to a negative end (i.e. connecting end 5002) ofthe DC output ends and the other end thereof electrically connects to ananode of diode D4. An anode of diode D4 electrically connects to apositive end (i.e. the connecting end 5001) of the DC output ends. Anend of the induction coil of transformer T2 electrically connects to asecond end of controller U2 and the other end of the induction coil isgrounded. A third end of controller U2 electrically connects to acontrol end of power switch Q2 through resistor R9. A first end of powerswitch Q2 electrically connects to a connecting point between diode D4and transformer T2, and a second end of power switch Q2 connects to afourth end of controller U2. Power converter 400 may be further providedwith a sampling circuit to sample its working status and serve as areference of output signal of the controller U2.

For example, the sampling circuit includes resistors R8, R10, capacitorC6 and an induction coil of the transformer T2. The controller U2 maysample voltage of the main line from resistor R8 and capacitor C6through its first end, sample output current from the induction coilthrough its second end and sample current flowing through the powerswitch Q2 from an end of resistor R10 through its fourth end.Configuration of the sampling circuit is related to the control mannerof the controller U2, the invention is not limited to this embodiment.

In this embodiment, at least one end of the switch controller U3electrically connects to a branch at which inductor L2 is located. Afiltering element and/or current stabilizer may be added between theswitch controller and the inductor. The present invention is not limitedthereto.

To reduce both influence resulting from harmonic to circuit propertiesand conversion loss, a power factor correction (PFC) circuit 300 may bedisposed between the power converter 400 and filtering circuit 200. ThePFC circuit 300 can increase power factors of the filtered signal byadjusting signal properties (e.g. phase, level or frequency) of thefiltered signal. PFC circuit 300 electrically connects to an output endof bias generating circuit 600. In detail, PFC circuit 300 may be anactive PFC circuit.

FIG. 77 is a circuit diagram of a PFC circuit of an embodiment of theinvention. As shown in FIG. 77, PFC circuit 300 receives signal from thefiltering circuit 300 through the connecting ends 301, 302 and sendscorrected signal to the post-stage power converter 400 throughconnecting ends 401, 402. PFC circuit 300 includes a controller U1, apower switch Q1 electrically connected to controller U1, a transformerT1 and a diode D3. Power switch Q1 may be a MOSFET. A first end (powerend) of the controller U1 electrically connects to an output end 607 ofbias generating circuit 600. A second end of controller U1 electricallyconnects to an end of transformer T1. A coil of transformer T1electrically connects to a main branch in series. The other end of thecoil electrically connected to a second end of controller U1 isgrounded. A positive end (also called connecting end 5001) of the DCoutput ends electrically connects to the main branch. Diode D3 iselectrically connected in the branch in series. An anode of diode D3electrically connects to both an end of transformer T1 and the filteringcircuit 200, and a cathode thereof electrically connects to connectingend 401 for electrically connecting to both power converter 400 andconnecting end 5001. A third end of controller U1 electrically connectsto power switch Q1. An end of power switch Q1 electrically connects to afifth electrically connecting point between diode D3 and transformer T1.Controller U1 may further electrically connects to a sampling circuit (aconnecting point between resistor R2 and capacitor C3 electricallyconnects to the controller U1, and capacitor C3 electrically connects toresistor R3 in parallel) and other circuits as shown in FIG. 77.

It should be noted that, the PFC circuit may have various implementationmanners or circuit configurations, all which can be applied to theinvention, so they would not be described here.

FIG. 79 is a circuit diagram of a bias generating circuit of the firstembodiment of the invention. As shown in FIGS. 75 and 79, biasgenerating circuit 600 a may include an electricity obtainer 610, aswitch controller U3 and an energy storage flyback unit 630. Electricityobtainer 610 electrically connects to both the input ends (ACN, ACL) andswitch controller U3. Switch controller U3 electrically connects toenergy storage unit 630 having an output end 607 for outputting aworking voltage (VCC). Output end 607 electrically connects to powerconverter 400 to provide the working voltage (VCC) to the powerconverter 400.

Switch controller U3 controls switching frequency of the energy storageunit 630 according to an electricity obtaining signal from theelectricity obtainer 610 to generate the working voltage of the powerconverter 400 and uses the output end 607 to output the working voltageto the power converter 400. The switch controller U3 is activated byresponding to the electricity obtaining signal from the electricityobtainer 610 and repeatedly switches on and off to periodically chargeand discharge by controlling conducting time of the energy storage unit630. And diode D5 is used to keep flyback. Thus, the working voltage ofthe power converter 400 is formed and is output to the power converter400 through the output end 607.

In an embodiment, the electricity obtainer 610 can convert AC drivingsignal into DC electricity obtaining signal which are equal to the ACdriving signal. As shown in FIGS. 75 and 79, electricity obtainer 610can be implemented by a second rectifying circuit (hereinafter “secondrectifying circuit 610”). Second rectifying circuit 610 includes a firstdiode D1 and a second diode D2, which are electrically connected inseries with opposite polarity (i.e. cathodes of diodes D1 and D2 areelectrically connected together). Second rectifying circuit 610 has anelectricity obtaining end 601 between diodes D1 and D2. The electricityobtaining end 601 electrically connects to the switch controller U3. Bythe opposite polarity, the two diodes D1 and D2 rectify the AC drivingsignal to output DC driving signal at the electricity obtaining end 601.

In detail, the electricity obtaining end 601 further electricallyconnects to an end of first capacitor C9, and the other end thereofelectrically connects to the ground end GND. Switch controller U3electrically connects to an end of inductor L2, and the other endthereof connects to the output end 607. Inductor L2 can perform bothenergy storage and release and maintain the current continuity whenswitch controller U3 is switching.

In this embodiment, energy storage flyback unit 630 may include aninductor L2, a third diode D5 and a second capacitor C11. A cathode ofthe third diode D5 connects to a connecting end 603 disposed between theswitch controller U3 and inductor L2. An anode of third diode D5connects to ground end GND. An end of second capacitor C11 electricallyconnects to a second connecting end 604 disposed between inductor L2 andthe output end 607. The other end of second capacitor C11 electricallyconnects to the ground end GND. an end of a load resistor electricallyconnects to a third connecting end (not shown in FIG. 75) disposedbetween the second connecting end 604 and the output end 607. The otherend of the load resistor electrically connects to ground end GND.

Further, switch controller U3 may be a MOSFET switch or an IC shipintegrated with a MOSFET switch. Of course, in some embodiments, switchcontroller U3 may be a BJT switch. Switch controller U3 has multipleconnecting ends (also called connecting port). An electricity obtainingbranch is formed between the electricity obtaining end 601 and theground end GND. The first capacitor C9 is connected in the electricityobtaining branch in series. At least one connecting end of switchcontroller U3 electrically connects to the electricity obtaining end 601through the electricity obtaining branch. A branch at which both theelectricity obtaining branch and capacitor C9 are located electricallyconnects to the electricity obtaining end 601 through the fourthconnecting end 602. The ground end GND electrically connected to agrounding line 640. All of the third diode D5, the second capacitor C11and the load resistor electrically connect to the grounding line 640.

The bias generating circuit 600 may be further provided with a samplingcircuit to sample its working status and to be a reference of outputsignal of the switch controller. In addition, in the practicalapplication, switch controller U3 may be a chip or IC integrated with atleast a control circuit and a power switch, but the present invention isnot limited thereto.

For example, the sampling circuit may include a first sampling circuit650 and a second sampling circuit 620. First sampling circuit 650electrically connects to both the electricity obtaining end 601 (forminga connecting point 605 in FIG. 79) and switch controller U3. The secondsampling circuit 620 electrically connects to both the output end 607and switch controller U3. Switch controller U3 outputs a stable workingvoltage according to sampling signal from both the first samplingcircuit 650 and second sampling circuit 620. Configuration of thesampling circuit is related to the control manner of switch controllerU3, the invention is not limited to this. FIG. 79 is a circuit diagramof the bias generating circuit of the first embodiment of the invention.

In other embodiments, the bias generating circuit may also be used forproviding a working voltage to a temperature sensing circuit 700. FIG.80 is a circuit diagram of the bias generating circuit of the secondembodiment of the invention. FIG. 81 is a circuit diagram of atemperature sensing circuit of an embodiment of the invention. As shownin FIGS. 80 and 81, the temperature sensing circuit 700 electricallyconnects to power converter 400 for sending temperature detecting signalto power converter 400. The temperature sensing circuit 700 has atemperature sensor electrically connecting to bias generating circuit600 b to make bias generating circuit 600 b provide a working voltage totemperature sensing circuit 600 b.

In this embodiment, in comparison with the embodiment shown in FIG. 79,the bias generating circuit 600 b of this embodiment further includes atransistor Q3, a diode D6, a resistor R12 and a capacitor C10.Transistor Q3 may be a BJT as an example (hereinafter refer as BJT Q3).The temperature detector 700 electrically connects to BJT Q3 of the biasgenerating circuit 600 b. The collector of BJT Q3 electrically connectsto output end 607. The base of BJT Q3 electrically connects to thegrounding line with the ground end GND.

The temperature sensing circuit 700 is activated by responding to theworking voltage provided by the bias generating circuit 600 b throughthe connecting ends 701 and 702 and feeds temperature data (Vtemp) backto the controller U2 of the power converter 400. When a temperatureexceeds a threshold value (indicating a situation of overheating), thecontroller U2 of the power converter 400 would reduce output power todecrease temperature and guarantee the safety during operation.

Moreover, as shown in FIG. 82, the temperature sensing circuit 700further electrically connects to a temperature compensator 800. FIG. 82is circuit diagram of a temperature compensator of an embodiment of theinvention. Temperature sensing circuit 700 electrically connects betweentemperature compensator 800 and bias generating circuit 600 b.Temperature compensator 800 electrically connects to power converter400.

Temperature compensator 800 makes a reference temperature of a free endof the temperature sensing circuit more reasonable. The temperaturecompensator 800 in this embodiment can be implemented by a comparator CP(but not limited to this). An input end of comparator CP receives avoltage, indicating a temperature information, through connecting end801 and compares the voltage indicating the temperature information witha reference voltage Vref of another input end of comparator CP, suchthat whether the temperature sensed by the temperature sensing circuit700 exceeds a threshold value can be determined and a temperaturesensing result signal Vtemp indicating whether the sensed temperatureexceeds a threshold value is generated at an output end of thecomparator CP. The output end of the temperature compensator 800electrically connects to the controller U2 of the power converter 400 tomake the temperature sensing result signal Vtemp fed back to controllerU2 of power converter 400, so that controller U2 can adjust the outputpower depending on the system environment temperature.

In another embodiment, the temperature compensator 800 may have aregulator diode and a thermistor. After the thermistor, the temperaturecompensator 800 electrically connects to an amplifier through anadjustable potentiometer. A negative end of the amplifier electricallyconnects to an output end of the temperature compensator 800.

In detail, a circuit diagram of the temperature compensator 800 may beas shown in FIG. 82. It should be noted that, the temperaturecompensator 800 can be implemented by various manners. The invention isnot limited to the circuit shown in FIG. 82.

The invention further provides a high power LED lamp including an LEDlight source 500 and a power supply module as abovementioned connectingwith the LED light source 500. In some embodiments, the high power LEDlamp means all types of LED lamps whose output power exceeds 30 w, LEDlamps which are equivalent to xenon lamps with output power of at least30 W or LED lamps using high power lamp beads (e.g. lamp beads withrated current above 20 mA).

All digital values mentioned in the description include all valuesbetween an upper limit and a lower limit with upper or lower values ofincrement or decrement by one unit, an interval of at least two unitsbetween any lower value and its higher value is available. For example,if a value of a recited quantity of an element or a process variable(e.g. temperature, pressure, time, etc.) is between 1 and 90,preferably, between 20 and 80, more preferably, between 30 and 70, itmeans inclusion of between 15 and 85, between 22 and 68, between 43 and51, between 30 and 32, etc. For a value less than 1, one unit may beproperly deemed as 0.0001, 0.001, 0.01 and 0.1. This merely intents toclearly express exemplary values. That is, all values and theircombinations between the lowest value and the highest value are includedin ranges described in the specification.

Unless otherwise defined, all ranges used herein include two end pointsand all numbers therebetween. The terms “approximately”, “about” or“similar” associated with the ranges are suitable for the two endpointsof the range. Thus, “about 20 to 30” intents to cover “about 20 to about30”, and at least includes the two endpoints indicated.

It will be further understood that the terms “comprises” and/or“comprising,” or “includes” and/or “including” or “has” and/or “having”when used herein, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Multiple elements, compositions, parts or steps can be provided by asingle integrated element, composition, part or step. Contrarily, asingle integrated element, composition, part or step can be divided intomultiple separate elements, compositions, parts or steps. As usedherein, the singular forms “a”, “an” and “the” are intended to includethe plural forms as well, unless the context clearly indicatesotherwise.

It should be understood that the above description is for the purpose ofdescribing particular embodiments only and is not intended to belimiting of the disclosure. Although the present disclosure isillustrated and described with reference to specific embodiments, thoseskilled in the art will understand that many variations andmodifications are readily attainable without departing from the spiritand scope thereof as defined by the appended claims and their legalequivalents.

The above depiction has been described with reference to theaccompanying drawings, in which exemplary embodiments of the disclosureare shown. This disclosure may, however, be embodied in many differentforms and should not be construed as limited to the embodiments setforth herein. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art.

What is claimed is:
 1. An LED (light emitting diode) lamp comprising: alamp shell; a passive heat dissipating element having a heat sinkconnected to the lamp shell, wherein the heat sink comprises fins and abase; a power source disposed in the lamp shell; and a light boardconnected to the base of the passive heat dissipating element andcomprising LED chips in an array arrangement electrically connected tothe power source; wherein a chamber of the lamp shell is formed with afirst heat dissipating channel, the first heat dissipating channel has afirst air inlet at a first end of the lamp shell, a second end of thelamp shell has at least a heat dissipating hole; wherein a second heatdissipating channel is formed in the heat sink and between the fins andbase, the second heat dissipating channel has a second air inlet, suchthat air flows from outside of the LED lamp into the second air inletand passes through the second heat dissipating channel, and flows outfrom spaces between every adjacent two of the fins.
 2. The LED lamp ofclaim 1, wherein the light board is formed with an aperturecommunicating simultaneously with both the first heat dissipatingchannel and the second heat dissipating channel.
 3. The LED lamp ofclaim 2, wherein the aperture is located in a central region of thelight board, and the aperture forms an air intake of both the first heatdissipating channel and the second heat dissipating channel.
 4. The LEDlamp of claim 1, wherein a weight of the heat sink accounts for at least50% of that of the LED lamp, and a volume of the heat sink accounts forat least 20% of an overall volume of the LED lamp.
 5. The LED lamp ofclaim 4, wherein a volume of the heat sink accounts for 20%˜60% of anoverall volume of the LED lamp.
 6. The LED lamp of claim 4, wherein theheat sink comprises first fins and second fins, bottoms of both thefirst fins and the second fins in an axis of the LED lamp connect to thebase, the first fins interlace with the second fins at regularintervals, and each of the second fins is of a Y-shape.
 7. The LED lampof claim 1, further comprising a lamp cover with a light output surfaceand an end surface, wherein the end surface is formed with a vent to letair flowing from outside of the LED lamp into both the first heatdissipating channel and the second heat dissipating channel through thevent, the first air inlet is projected onto the end surface in an axisof the LED lamp to occupy an area on the end surface, which is definedas a first portion, another area on the end surface is defined as asecond portion, and the vent in the first portion is greater than thevent in the second portion in area.
 8. The LED lamp of claim 7, whereina ratio of area of the light output surface to area of the end surfaceis 4˜7.
 9. The LED lamp of claim 7, wherein a ratio of area of the lampcover to area of the end surface is 6˜7.
 10. The LED lamp of claim 7further comprising an inner reflecting surface disposed inside the lightoutput surface of the lamp cover, wherein the inner reflecting surfaceis disposed in a position of an inner circle of the array of the LEDchips.
 11. The LED lamp of claim 10 further comprising an outerreflecting surface disposed in the outer circle of the array of the LEDchips, wherein the outer reflecting surface is set to correspond to theLED chips on the light board.
 12. The LED lamp of claim 11, wherein theinner reflecting surface is configured to reflect part of light emittedfrom the innermost of the array of LED chips, the outer reflectingsurface is configured to reflect part of light emitted from theoutermost of the array of LED chips, and the outermost of the array ofLED chips are greater than the innermost of array of LED chips innumber, and the outer reflecting surface is greater than the innerreflecting surface in area.
 13. The LED lamp of claim 12, wherein arelationship as follows is satisfied between the LED chips and the innerand outer reflecting surface:(A1/N1):(A2/N2)=0.4˜1 where A1 and A2 respectively represent area of theinner and outer reflecting surface; where N1 and N2 respectivelyrepresent number of the innermost and outermost of the array of LEDchips of the light board.
 14. The LED lamp of claim 11, wherein an angleis formed between two extending lines of both the inner and outerreflecting surfaces, and the angle is between 80 degrees and 150degrees.
 15. The LED lamp of claim 7 further comprising a chamber formedbetween the light cover and the light board, and the light board and theLED chips of the light board are located in the chamber.
 16. The LEDlamp of claim 7, wherein the distance between the light output surfaceand the light board is gradually outwardly larger and larger, such thatthe light output surface is made concave in shape.
 17. The LED lamp ofclaim 1 further comprising a third heat dissipating channel formedbetween adjacent two of the fins or in a space between two sheetsextending from a single of the fins of the heat sink, such that airflows from outside of the LED lamp into the third heat dissipatingchannel through the radial outer portion of the LED lamp to bring outheat radiated from the heat sink to air.
 18. The LED lamp of claim 1,wherein the base of the heat sink further has a lower end located underthe base and protruding from the light board in an axis direction of theLED lamp.
 19. The LED lamp of claim 1, wherein the fins of the heat sinkcomprises a first portion and a second portion in a radial direction ofthe LED lamp, and the first portion is less than the second portion incurvature.
 20. The LED lamp of claim 1, wherein the heat sink includesfirst heat dissipating units and second heat dissipating units, both thefirst heat dissipating units and the second heat dissipating units areof fin type; wherein each of the first heat dissipating units includes afirst fin radially arranged on the heat sink and a radial first channel,the first channel is a gap between two of the first heat dissipatingunits.